J*3_ 


*V    »"    'A    •***     S^*~\ 

•|,|6^ 


N  ;•'/<>-'  -4JM    *9  i    NA;  -^ 


I^?*^ 


V^jgSf  '       A    ^U^r* 


^ 


UNIVERSAL 
WIRING  COMPUTER 


FOR  DETERMINING 

The  Size  of  Wires  for  Incandescent  Electric 
Lamp  Leads 

AND  FOR  DISTRIBUTION  IN  GENERAL, 

Without  Calculation,  Formulas  or  Knowledge  of  Mathematics 

WITH  SOME  NOTES  ON  WIRING  AND  A  SET  OF 

AUXILIARY  TABLES. 

BY 

CARL  HERING 


NEW  YOEK: 
THE  W.  J.  JOHNSTON  COMPANY,  LTD. 

1891 


2- 


Copyright,  1891,  by  Carl  Bering. 


PREFACE. 


IN  submitting  to  the  public  the  accompanying  new  system  for 
determining  the  size  of  leads  without  calculations,  the  author 
desires  to  say  that  he  has  endeavored  to  make  the  charts  as  simple 
and  practical  as  possible;  but,  as  in  other  new  departures,  it  is 
possible  that  such  proportions  as  the  dimensions  of  the  scales, 
their  ranges,  the  size  of  the  charts,  the  limit  of  accuracy,  etc., 
might  be  more  advantageously  chosen  so  as  to  bring  the  average 
values  to  the  best  parts  of  the  charts.  As  the  values  for  the< 
usual  determinations  have  such  very  wide  limits,  it  is  difficult  to 
determine  on  the  best  proportions  of  the  charts  except  by  long 
and  repeated  use  in  practice  under  widely  differing  circumstances. 
Since  this  can  best  be  done  by  the  aid  of  those  using  this  system 
under  different  circumstances,  the  author  appeals  to  those  using 
these  charts  to  aid  him  in  finding  the  most  convenient  propor- 
tions, by  suggesting  to  him  any  changes  in  the  present  proportions 
gained  from  actual  experience  with  the  charts.  Such  changes 
will,  if  practicable,  be  embodied  and  duly  acknowledged  in  subse- 
quent editions,  of  which  copies  will  be  sent  to  those  to  whose 
kindness  the  author  owes  the  changes. 

As  its  title  indicates,  this  book  is  intended  to  facilitate  the 
computing  of  the  size  and  quantity  of  wire  used  for  wiring ;  it  is 
not  a  treatise  on  wiring,  but  assumes  a  knowledge  of  wiring  on  the 
part  of  the  reader.  It  is  intended  for  a  book  of  reference,  and  not 
for  a  book  of  instruction.  The  auxiliary  tables,  which  were  almost 
all  calculated  for  this  book,  are  limited  to  those  which  wiremen 
frequently  have  occasion  to  refer  to. 

The  author  is  indebted  to  his  friend  Richard  W.  Davids  for 
some  practical  suggestions,  and  to  the  ELECTRICAL  ENGINEER  for 
the  use  of  some  of  the  illustrations. 

CARL  HERING. 

Philadelphia,  April,  1891.  &  «>  7  b  8 


CONTENTS. 


PAGE 

Introduction 1 

Explanation  of  the  Charts 3 

Hints  and  Modifications 4 

Charts following    8 

Distribution  of  Incandescent  Light  Leads 9 

Fusible  Cut  Outs 17 

Wiring  Formulae.   Their  Deduction  and  Use 18 

Tables : 

Tables  of  Wire  Gauges  ...       23 

Table  of  Compounded  Wires  of  Large  Cross  Section 28 

Table  of  the  Weight  and  Eesistance  of  Copper  Wire 30 

Table  of  Temperature  Corrections  for  Copper  Wire 32 

Weight  of  Insulated  Wire  for  Wiring 33 

Table  of  Heating  Limits  or  Maximum  Safe  Carrying  Capacity 

of  Insulated  Wires 34 

Table  of  Horse  Power  Equivalents 35 

Wiring  Tables 38 


UNIVERSAL  WIRING  COMPUTER. 


INTRODUCTION. 


THE  determination  of  the  proper  size  of  the  wire  for  distribut- 
ing current  for  incandescent  lighting,  is  burdened  with  the  use 
of  formulae  having  "  constants  "  varying  with  each  style  of  lamp ; 
these  constants  mean  different  things,  depending  on  which  formula 
is  used;  furthermore  many  wiremen  and  contractors  may  not 
know  how  this  constant  is  determined,  and  therefore  they  cannot 
deduce  it  themselves  if  they  have  forgotten  it,  or  if  they  have  to 
wire  for  a  different  make  of  lamp.  Such  formulae  and  constants 
are  therefore  often  unsatisfactory  for  all  cases  except  for  daily 
work  with  one  particular  make  of  lamp.  Even  then  there  is  no 
small  amount  of  calculation  necessary  to  make  a  proper  determi- 
nation of  the  wiring  of  a  building;  the  natural  consequence  is 
that  much  of  the  wiring  is  a  mere  guess  as  to  the  size  of  wire,  and 
it  is  a  matter  of  chance  whether  this  guess  is  a  good  one  or  a  bad 
one.  The  sizes  of  wire  may  be  so  widely  different  for  differing 
conditions,  that  a  "  guess  "  is  more  likely  to  be  a  bad  one,  except, 
perhaps,  in  the  unfrequent  case  of  a  person  making  very  many 
determinations  daily  for  the  same  make  of  lamp ;  even  in  such 
cases  it  is  well  to  check  the  results  by  a  proper  determination. 
The  competition  among  contractors  for  wiring  is  getting  to  be  so 

(1) 


;  JNTkCDUCTION. 


great  thaVfit;^iJ2:;l>f*  tttfc  ,w&  who  makes  the  most  economical 
determination  of  the  sizes  of  wire,  who  will  be  able  to  outbid  his 
competitors  who  may  either  waste  wire  in  making  it  too  large,  or 
have  to  add  an  additional  wire  afterwards  in  case  it  was  too  small. 
The  cause  of  much  of  this  "  guessing  "  is  doubtless  due  to  the 
fact  that  it  requires  no  small  amount  of  figuring  to  make  even  an 
approximate  determination  of  the  sizes  of  the  wire.  It  is  to 
diminish  this  work  that  the  author  has  devised  the  accompanying 
charts,  by  means  of  which  all  such  determinations  are  made  at  a 
glance,  more  readily  even  than  if  the  values  were  looked  up  in 
tables  (if  such  tables  existed),  which  would  necessarily  have  to  be 
very  bulky  and  cumbersome,  in  order  to  cover  such  a  wide  range 
as  that  required  for  the  general  practice. 


EXPLANATION  OF  THE  CHARTS. 


GENERAL. — These  charts  will  give  directly  and  without  calcula- 
tion or  the  use  of  formulae,  the  gauge  number  or  cross-section 
in  circular  mils  of  leads  for  any  number  of  lamps  of  any  make,  at 
any  distance  and  for  any  loss.  There  are  three  charts  with  differ- 
ent scales,  covering  the  following  ranges : 

Few  lamps  at  short  distances. 

Few  lamps  at  long  distances. 

Many  lamps  at  short  distances. 

Also  a  blank  chart  which  can  be  filled  out  for  any  special 
ranges,  as  will  be  described  below.  The  ranges  overlap  somewhat, 
so  that  if  the  values  sought  for  are  on  awkward  parts  of  the  charts, 
they  will  probably  be  found  in  better  parts  on  one  of  the  other 
charts.  They  cover  the  ranges  for  house  wiring,  for  large  or  small 
houses,  and  give  the  results  with  a  degree  of  accuracy  which  is  far 
greater  than  is  necessary  on  account  of  the  wide  limits  between 
the  standard  sizes  of  wire  in  the  market ;  a  greater  accuracy  than 
this  would  be  absurd,  as  one  cannot  generally  obtain  the  wire  for 
any  but  the  regular  sizes,  and  not  even  for  all  of  these.  For  many 
lamps  at  a  great  distance,  a  small  error  would  make  a  great  differ- 
ence in  the  cost  of  the  wire.  For  such  cases  the  wire  must  be  cal- 
culated by  means  of  the  usual  formula,  for  which  see  page  19. 

How  TO  USE  THE  CHARTS. — The  vertical  scale  just  below  the 
center  represents  the  current  in  amperes  for  one  lamp.  Find  the 
current  of  the  particular  make  of  lamp  on  this  scale,  and  follow 
it  horizontally  to  the  left  until  it  intersects  the  diagonal  represent- 
ing the  desired  loss  in  volts  (see  broken  line  on  charts) ;  from  this 
intersection  follow  the  corresponding  vertical  line  until  it  inter- 
sects the  diagonal  in  the  upper  left  hand  portion,  representing  the 
desired  number  of  lamps ;  from  this  intersection  follow  horizon- 
tally to  the  right  to  the  next  set  of  diagonals  representing  the  dis- 
tances in  feet  (not  the  length  and  return,  but  merely  the  distance 
one  way),  and  from  this  intersection  follow  down  vertically  to  the 
scale  which  gives  the  circular  mils,  as  also  the  B.  &  S.  (American) 

(3) 


4  WIRING   COMPUTER. 

wire  gauge  numbers.  An  example  is  worked  out  on  each  chart 
and  indicated  on  the  chart  by  a  broken  line. 

It  should  be  noticed  that  the  loss  is  given  in  volts,  and  not  in 
per  cent.,  except  for  a  100-volt  lamp,  for  which  the  loss  in  per 
cent,  and  in  volts  is  the  same  thing.  For  any  other  voltage,  if 
the  loss  is  given  in  per  cent.,  find  the  number  of  volts  which  this 
represents  before  starting  to  use  the  chart.  This  is  done  by  mul- 
tiplying the  voltage  of  the  lamp,  say  75  volts,  by  the  per  cent., 
say  2  per  cent.,  and  divide  by  100 ;  thus,  75  x  2  -r-  100  =  1.5  volts. 

HINTS  AND  MODIFICATIONS. 

"  FOR  ONE  PARTICULAR  MAKE  OF  LAMP. — If,  as  is  generally  the 
case,  a  large  number  of  determinations  are  to  be  made  for  one 
particular  make  of  lamp,  the  work  can  be  shortened  considerably 
by  laying  off  with  care,  on  the  first  scale,  the  current  for  that  lamp, 
and  then  with  a  lead  pencil  or  red  ink  draw  a  bold  horizontal  line 
across  to  the  left.  The  intersections  of  this  line  with  the  volt 
diagonals  will  then  be  the  starting  points  for  the  different  losses. 
The  numbers  which  the  diagonals  represent  can  then  be  trans- 
ferred to  this  line  for  convenience. 

FOR  ONE  PARTICULAR  Loss. — If,  besides  using  the  same  lamp 
the  loss  is  also  the  same  for  a  large  number  of  determinations, 
which  is  very  often  the  case,  then  draw  a  second  red  line,  or  bold 
pencil  line,  vertically  upward  across  the  "  lamp  "  diagonals,  then 
these  intersections  (in  the  upper  left  hand  field)  will  be  the  start- 
ing points  for  all  determinations,  thus  simplifying  the  work  by 
reducing  it  to  one-half.  It  is  recommended  in  this  case  to  transfer 
the  numbers  representing  the  lamps  to  the  intersections  of  this 
new  line,  with  the  respective  diagonals  in  that  field,  as  these  inter- 
sections form  the  starting  points. 

STANDARD  SIZES  OF  WIRES. — The  work  is  still  further  simplified 
by  the  vertical  dotted  lines  in  the  right  hand  field  which  have  been 
drawn  through  the  gauge  numbers  on  the  scale  which  represent 
the  standard  B.  &.  S.  sizes  of  wire.  This  facilitates  following  the 
vertical  lines  down  to  the  scale,  thus  reducing  the  amount  of  work 
still  more. 

Loss  IN  PER  CENT.  INSTEAD  OF  VOLTS. — If  it  is  preferable  to 
have  the  losses  read  in  per  cent,  instead  of  in  volts,  the  change 
can  be  made  by  calculating  what  percentages  are  represented  by 


EXPLANATION    OP   THE    CHARTS.  5 

each  of  the  volt  lines,  and  marking  them  accordingly.  But  such 
figures  will  be  correct  only  for  lamps  of  that  same  voltage,  and  for 
no  other. 

INTERPOLATING. — For  values  lying  between  two  diagonals,  or 
when  new  diagonals  are  drawn  for  special  values  (as,  for  instance, 
for  one  standard  loss  in  volts),  notice  that  in  the  lower  left  hand 
field  the  distances  between  the  diagonals  should  be  measured  on 
a  vertical  scale  on  which  they  are  proportional  to  the  volts ;  for 
instance,  a  diagonal  representing  1 J-  volt  would  be  half  way  be- 
tween that  for  1  volt  and  that  for  1 J  volt,  measured  on  any  vertical 
line,  and  not  on  a  horizontal  line  nor  on  the  arc  of  a  circle.  The 
same  thing  is  true  of  the  upper  left  hand  field  (lamps),  namely, 
that  the  vertical  scale  is  quite  regular.  In  the  upper  right  hand 
field  (feet),  it  is  the  horizontal  scale  and  not  the  vertical  which  is 
regular. 

CHANGING  THE  SCALES. — The  following  points  are  worth  re- 
membering. The  number  of  lamps  and  the  distances  in  feet  are 
interchangeable.  It  may  be^  more  convenient  sometimes  to  use 
lamps  for  feet  and  feet  for  lamps ;  both  give  the  same  result.  Fur- 
thermore, either  of  these  two  may  be  divided  or  multiplied  by  2, 
or  10,  or  100,  etc.,  if  the  other  one  is  correspondingly  multiplied  or 
divided  by  the  same  factor.  For  instance,  1  lamp  at  400  feet  is 
the  same  as  2  lamps  at  200  feet,  or  4  lamps  at  100  feet.  Some- 
times one  or  the  other  of  these  alternatives  is  more  convenient  to 
find.  With  the  volt  scale,  however,  it  is  different ;  if  the  volt 
figures  are  multiplied  by  two,  for  instance,  the  lamp  figures  (or 
the  feet)  must  be  multiplied  (not  divided)  by  two  also ;  for 
instance,  for  a  1-amp.  lamp  and  a  J-volt  loss,  the  intersection  falls 
off  the  chart ;  but  by  using  the  1-volt  diagonal  instead,  and  doub- 
ling the  number  of  lamps  (or  the  feet),  the  final  result  will  be  the 
same.  Such  changes  are  rarely  necessary,  on  account  of  the  dif- 
ferent ranges  of  the  different  charts;  but  it  may  often  be  less 
trouble  to  take  such  an  alternative  than  to  turn  to  another  chart. 

SPARE  CHARTS. — A  spare  chart  has  been  added  on  which  the 
lines  are  identical  with  those  on  the  other  charts.  This  may  be 
filled  out  with  figures  so  as  to  cover  any  special  work,  as,  for 
instance,  for  the  three- wire  system,  for  motor  work,  or  perhaps  for 
improvements  on  the  ranges  of  the  scales  of  the  other  charts.* 

*  See  Preface. 


6  WIRING   COMPUTER. 

The  two  preceding  paragraphs  will  explain  in  what  proportions  the 
numbers  may  be  changed  without  changing  the  lines  themselves. 
Spare  charts  may  be  obtained  from  the  publisher. 

LAMPS  OF  DIFFERENT  CANDLE-POWERS. — If  lamps  of  different 
candle-power  (that  is,  having  different  currents)  are  mixed  and 
are  on  the  same  circuit,  they  must  either  all  be  reduced  to  their 
equivalent  in  terms  of  the  same  lamp,  or  else  if  there  are  only  two 
or  three  kinds,  the  leads  may  be  determined  in  circular  mils  (not 
in  gauge  numbers)  for  each  batch  of  like  lamps  separately,  and 
the  sum  of  all  the  circular  mils  taken,  from  which  sum  the  gauge 
numbers  are  .then  found  from  a  table  or  from  the  double  scale  on 
the  chart. 

POWER  LEADS. — For  the  distribution  of  power,  start  with  the 
line  (near  the  bottom  of  the  chart)  representing  a  one-ampere  lamp, 
then  the  numbers  representing  lamps  in  the  upper  left  hand  field 
will  represent  amperes  of  current.  The  current  in  amperes  cor- 
responding to  the  horse-power  must,  of  course,  be  determined 
first  from  the  horse-power  and  the  volts  (see  table  of  horse-power 
equivalents,  pages  36  and  37). 

THREE-WIRE  SYSTEM.—  If  the  wiring  is  to  be  done  for  the  three- 
wire  system  in  which  three  wires  of  like  size  are  used  in  place  of 
two,  the  cross-section  of  each  will  be  one-fourth  as  great  as  that 
for  the  ordinary  system. ,  Instead  of  finding  the  cross-section  from 
the  charts  and  dividing  it  by  four,  and  then  finding  the  gauge 
number  from  a  table,  it  is  much  simpler  to  proceed  as  before,  but 
taking  either  one-fourth  the  number  of  lamps  or  one-fourth  of  the 
distance,  or  four  times  the  loss.  By  doing  it  in  this  way  the  size 
of  wire  is  obtained  directly  without  the  use  of  any  table,  while  the 
only  calculation  necessary  is  merely  a  mental  one. 

OTHER  USES  OF  THE  CHARTS. — The  charts  may  be  used  back- 
ward, so  to  speak,  by  starting  with  a  given  size  of  wire  and  work- 
ing backward  to  find  what  the  loss  will  be  for  a  given  number  of 
lamps  at  a  given  distance.  In  the  same  way,  the  allowable  number 
of  lamps  or  the  distance  may  be  determined  if  the  other  quantities 
are  given.  In  general,  any  one  of  the  quantities  may  be  found  if 
all  the  others  are  given ;  the  general  rule  in  that  case  is  to  start 
from  the  beginning  and  end  of  the  chart  simultaneously,  and  con- 
tinue as  usual  until  the  two  lines  which  one  is  following  intersect 
in  the  common  field  which  contains  the  diagonals  representing 
the  quantity  looked  for;  that  diagonal  which  passes  through 


EXPLANATION  OF  THE   CHARTS.  7 

or  nearest  to  this  intersection  represents  the  number  sought 
for.  For  instance,  how  many  .775-ampere  lamps  will  a  No. 
11  wire  carry,  to  a  distance  of  50  feet,  with  a  loss  of  1  volt? 
See  the  first  chart,  broken  line.  Starting  with  the  line  represent- 
ing a  .775-ampere  lamp,  follow  it  to  the  1  volt  loss  line ;  thence  up 
into  the  field  representing  lamps ;  then  begin  with  the  intersection 
of  the  dotted  line  representing  a  No.  11  wire  and  the  50  feet  line, 
and  follow  backward  (see  broken  line)  to  the  lamp  field ;  where 
it  crosses  the  other  line,  find  what  diagonal  passes  through  this 
point ;  this  diagonal,  namely  10  lamps,  is  the  required  number 
of  lamps. 

AUXILIARY  TABLES. — At  the  end  of  the  book  there  are  some 
tables  which  will  frequently  be  found  useful  in  connection  with 
wiring  determinations. 

MANY  LAMPS  AT  A  GREAT  DISTANCE. — If  the  leads  are  to  be 
determined  for  many  lamps  at  a  great  distance,  a  small  error  in 
the  determination  signifies  a  considerable  difference  in  cost  of  the 
wire  ;  the  computation  must  therefore  be  made  more  accurately. 
To  do  this  would  require  a  chart  of  very  great  size.  It  is  there- 
fore preferable  to  calculate  such  exceptional  determinations  by 
means  of  one  of  the  following  rules : 

If  the  total  current  is  given :  multiply  the  total  current  by  the  dis- 
tance in  feet  and  by  21.21,  and  divide  by  the  loss  in  volts  ;  the  result 
will  be  the  required  cross-section  of  the  leads  in  circular  mils. 

If  the  current  per  lamp  is  given  :  multiply  the  current  per  lamp 
by  21.21 ;  this  gives  the  "  constant ";  multiply  the  number  of  lamps  by 
the  distance  in  feet  and  by  this  "  constant"  and  divide  by  the  loss  in  volts; 
the  result  will  be  the  required  cross  section  in  circular  mils. 

The  gauge  numbers  corresponding  to  these  cross  sections  will 
be  found  in  the  tables  at  the  end  of  the  book,  page  23.  For  very 
large  cross  sections  a 'table  is  given  showing  what  sizes  of  wires 
bunched  together  will  make  this  cross-section.  (See  page  28). 

BASIS  OF  THE  CHARTS. — The  basis  of  these  charts  (as  also  that 
of  the  tables  and  formulae  in  this  book)  is  a  resistance  of  10.61 
legal  ohms  per  mil  foot  of  copper  wire.  In  terms  of  the  Matthies- 
sen  standard  suggested  by  the  Committee  of  the  American  Insti- 
tute of  Electrical  Engineers  (namely,  9.612  legal  ohms  per  mil 
foot  at  0°  C.),  this  is  equivalent  to  the  resistance  at,  about  75°<  to 
80°  F.  As  pure  copper  of  the  present  time  sometimes  has  even 
less  resistance  than  that  referred  to  in  this  standard,  it  is  thought 


8  WIRING  COMPUTER. 

that  the  value  chosen  for  these  charts  and  tables  represents  a  fair 
t  .value  for  the  resistance  of  good  copper  at  the  average  normal  tem- 
perature. As  the  accidental  differences  in  the  'actual  diameters  of 
the  wires  introduce  errors  far  greater  than  a  slight  difference  in 
the  assumed  standard  conductivity,  it  would  not  be  reasonable  to 
attach  much  importance  here  to  great  precision  in  the  assumption 
of  the  standard.  All  that  is  necessary  here  is  to  select  the  fairest 
possible  value  for  actual  practice,  to  state  what  this  value  is,  and 
to  have  it  the  same  throughout  this  whole  set  of  charts,  tables  and 
formulae. 


12 

Li 

in 

p.9 

1 

1 

1 

I 

18 

20 

22 

ft 

i 

20 

30 

i 

6 

4 

) 

50 

i 

(1 

: 

•n 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

| 

\ 

i 

\ 

1 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

S 

x 

\ 

\ 

\ 

\ 

\ 

11  v 

\ 

\ 

\ 

1 

\    5 

\ 

\ 

1 

\ 

\ 

v. 

\ 

\ 

\ 

5 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

1 

& 

\ 

\ 

\ 

\ 

\ 

k 

V 

\ 

\ 

• 

\ 

^ 

• 

Q  10 

\ 

\ 

s, 

\ 

\ 

^ 

\s 

\ 

\ 

N 

\ 

^. 

\ 

\ 

\ 

\ 

X 

, 

V 

\ 

N 

\ 

\ 

1 

\ 

\ 

\ 

\^ 

^ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

1 

9 

\ 

\ 

k 

\ 

] 

\ 

\ 

' 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

> 

\ 

\ 

\ 

^ 

\ 

V 

\ 

\ 

\ 

\ 

-x 

s, 

! 

\ 

\ 

JL 

\ 

\ 

\  s 

\ 

\ 

\ 

8^ 

Vy 

\       \ 

N 

\ 

\ 

\ 

^ 

\ 

X 

x. 

Vy 

\ 

\ 

s, 

\ 

N. 

\ 

\ 

\ 

\ 

s 

^ 

x^ 

\ 

\ 

s,   \ 

\  \ 

\ 

~ 

, 

\ 

x 

\ 

'    , 

X 

\ 

•\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

^ 

- 

\ 

7> 

x 

\ 

- 

\ 

- 

\ 

\ 

\ 

\ 

^ 

\ 

I 

X 

X 

V 

\ 

V 

Vk 

\ 

\ 

\ 

; 

\ 

, 

•^ 

; 

N 

\ 

\ 

N, 

\ 

\ 

\ 

\ 

\ 

\ 

- 

\ 

\ 

'•• 

X 

\ 

s 

X 

\ 

So 

s. 

\ 

x^ 

\ 

\ 

\ 

i 

\ 

\ 

\ 

1 

JL 

6s 

s 

K^ 

x^ 

s 

S^ 

x      > 

v 

\ 

\ 

^ 

\ 

\\ 

\ 

\ 

V 

\ 

X 

.. 

x 

x 

x. 

s  s^ 

\ 

\ 

\ 

\ 

\ 

\ 

i 

\ 

^ 

X 

t 

' 

> 

v 

-. 

X 

•• 

>y 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

f 

\ 

\\ 

^_ 

\ 

., 

x, 

X 

\ 

v 

\^ 

x- 

\ 

s 

\ 

\ 

\ 

^ 

\ 

\ 

\ 

1 

\, 

\\     ~ 

5, 

"X 

s. 

X 

• 

X. 

x 

\ 

\ 

\ 

\ 

\ 

\\l 

\ 

\ 

h 

\\ 

**• 

^ 

\ 

x 

X 

N.        x 

\ 

\ 

S 

\ 

\  ' 

\ 

• 

\ 

\  \ 

•s^ 

X 

x^ 

X 

X^ 

X 

x  X, 

\ 

\ 

\ 

- 

\ 

A 

\\ 

\ 

\ 

\ 

\ 

\ 

~ 

«s 

'^ 

^ 

v 

X 

K. 

N 

x^ 

" 

•\ 

\ 

. 

s^ 

, 

\ 

\ 

\ 

S  "N 

|T 

\ 

\ 

\ 

\ 

LI: 

4^ 

s^ 

•x. 

X 

s^ 

\ 

\ 

•  ,  A 

*- 

—  r- 

jr 

A 

_\ 

- 

\- 

— 

' 

•^. 

• 

^ 

^ 

\    " 

x 

X 

s 

x, 

\ 

s^ 

s\ 

\ 

V 

\ 

\ 

\ 

"1  jj 

^ 

.. 

x 

•^ 

>s 

x^ 

X 

X^ 

s 

Kx 

\ 

'- 

s^ 

5 

\ 

\ 

, 

\  \ 

P. 

- 

. 

-^ 

--. 

Xv, 

X 

., 

X 

Xs- 

x^ 

s 

\k 

\ 

" 

\ 

\ 

\ 

\ 

\\  ' 

B    3, 

" 

"*• 

^, 

^s, 

" 

^     - 

Xs, 

x 

s^ 

> 

X, 

\ 

\ 

-  ^ 

s.\ 

\  \ 

\ 

\ 

\\ 

^ 

1     . 

"-.^ 

- 

~^ 

•^ 

x 

X, 

x 

v^ 

x^ 

s 

x 

s 

^v 

Sk^ 

s 

\ 

5 

V 

\ 

f 

\ 

*~-~. 

^^ 

•V. 

-^- 

^ 

X 

s" 

x 

x 

s 

\ 

'\ 

\ 

\ 

\ 

3 

,    i  \ 

: 

-• 

••*• 

•»». 

^ 

•^^ 

""* 

X, 

X 

N 

x 

S 

\ 

\ 

s 

s 

\ 

Mt 

fr 

— 

. 

- 

^. 

~-^»^ 

-^ 

^ 

"^-^ 

•x 

|^ 

^ 

X^ 

X 

\ 

\ 

\ 

\ 

v  ^N 

v  V\ 

—  . 

1  

~ 

~- 

--  .., 

-> 

^^ 

^ 

L^ 

s 

x 

X 

^s 

s 

\ 

\ 

V 

\\  \\\ 

"  •     ^ 

—-— 

- 

-_ 

^_^ 

^ 

>^, 

^ 

X. 

X. 

\ 

sv 

sssl 

s\ 

\ 

\ 

S^-  5 

"  — 

-- 

"^-v. 

•N. 

*^. 

"X 

s, 

s 

V\   k\    \ 

I- 

7 

«= 

=r 

^z 

—  ~ 

—  . 

•=- 

—  .- 

\ 

—  - 

~ 
"-^      ™ 

--^- 

-^-^ 

"-] 

*—  *. 

-  — 
-  -  — 

-  — 

-a- 

=  =a 

=»=- 

^=r 
"—  . 

~ 
»^- 
—  »=: 

\ 

-^i. 
=i 

->^ 

—  - 

-«=i 
±s 
«• 

-^Z 
z=^ 

•^-C 

^^ 
— 

•~- 

—  . 

r^. 
=^ 

^C 

-^^ 

•-^ 
^z 

t" 

•v 

5^^ 
±: 
1^— 
-—  . 

•^ 

x, 

-^ 
*^ 

—  . 

i 

^1 

i 

\ 

1 

~-~- 

^-f 

- 

— 

—  ' 

f 

-— 

-^ 

^~ 

^*- 

r^ 

I 

-— 

^ 

.-^ 

^** 
~ 

^ 

.  —  " 
^ 

H% 

.  — 

- 

^ 

^ 

s 

' 

/ 

'4 

/ 

//  'i 

— 



^-i 

.'- 

s 

/ 

,. 

/  n 

.2- 

—  • 

—  • 

*~* 

—  < 

=• 



r-:T 

,  ^ 

-:' 

<£.*- 

;;; 

^^ 

^ 

-^ 

s 

-^ 

•? 

7* 

/ 

Z 

,/1 

^ 

, 

' 

^f 

^ 

g 

S 

• 

/ 

-'  / 

/ 

/I 

]•— 

.... 

^~- 

-- 

^ 

,, 

/ 

'  J 

/ 

i 

/ 

_.._. 

- 

" 

^ 

^ 

,-• 

? 

/ 

/ 

/ 

2 

- 

Lu 

.3- 

** 

s 

/' 

/> 

^ 

/ 

i 

: 

\f 

. 

^ 

~ 

J^ 

-' 

^ 

/ 

/ 

' 

/ 

~LL  * 

•3 

^* 

-*" 

-      ' 

^ 

^ 

s 

/ 

/ 

/ 

/ 

I 

^ 

-- 

- 

s 

/ 

/^ 

/ 

_/      * 

a  A 

•• 

/ 

"    / 

i— 

" 

± 

•t  — 

tD 

/> 

/ 

/ 

/ 

/ 

/ 

o 

s 

? 

• 

/ 

/ 

/ 

/ 

/ 

/ 

/ 

, 

t 

s" 

' 

*- 

S 

•••- 

s 

1 

' 

: 

"s 

,. 

s 

. 

, 

, 

/ 

i 

I 

^ 

^ 

' 

,, 

^ 

/ 

1 

/ 

i 

I 

.6' 

,.- 

^ 

-• 

, 

/ 

'. 

1 

• 

/f 

/ 

/ 

' 

1 

.7 

Loss  in  volts. 


.9        1.  1.2  1.5 


Copyright,  1891, 


98  7 

B.  &  S.  Gauge  Numbers. 


FEW  LAMPS  AT  SHORT  DISTANCES. 

Rule  for  using  the  chart: 

Follow  the  general  direction  of  the  broken  line  and  the  arrows,  from 
one  set  of  diagonals  to  the  next. 

EXAMPLE:  What  size  wire  is  required  for  10  lamps  of  .775  amperes  each,  at  50  feet,  for 
a  loss  of  1  volt? 

SOLUTION  :  Starting  with  the  current  for  1  lamp,  .775  amperes  (see  scale  below  center), 
follow  it  (see  broken  line  and  arrows)  to  the  left,  until  it  intersects  the  diagonal  represent- 
ing 1  volt  loss ;  thence  up  to  the  diagonal  representing  10  lamps  ;  thence  to  the  right  to 
the  diagonal  representing  50  feet,  and  from  here  down  to  the  scale  of  the  circular  mils 
or  gauge  numbers,  on  which  the  reading  is  found  to  be  about  8,200  circular  mils,  or  a 
No.  11  B.  &  S.  wire. 

For  a  more  detailed  explanation,  abbreviated,  raetbods-and  gerv»?ral5iiots,  see  text. 


ARL  IIERING. 


12        Lamps       14 


18        20      22     24    26        30       35     40        50    60  70          Lamps 


\ 

S 

s 

\ 

\ 

\ 

\ 

| 

\ 

" 

t 

i 

\ 

\ 

\ 

\ 

\ 

^ 

\ 

\ 

\ 

\ 

3 

\ 

\ 

\ 

\ 

i 

\ 

11 

\ 

\ 

\ 

V 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

^ 

\ 

\ 

\ 

\ 

\ 

n, 

\ 

\ 

\ 

\ 

' 

\ 

\ 

\ 

- 

R10 

. 

\ 

\ 

. 

v 

\ 

,1 

5 

\ 

\ 

\ 

\ 

^y 

\ 

\ 

\ 

\ 

• 

\ 

\ 

- 

\ 

\ 

\ 

- 

\ 

\ 

' 

\ 

\ 

\ 

. 

\ 

\ 

\ 

1 

9% 

x 

\ 

\ 

\ 

\ 

\ 

\ 

'• 

\ 

\ 

- 

• 

\ 

J 

\ 

\ 

,' 

\ 

\ 

V 

\ 

\ 

•• 

\ 

\ 

\ 

• 

A 

\ 

u 

*  i  — 

—  i— 

8> 

S^ 

S. 

i 

* 

- 

\ 

^ 

i 

i_ 

i  T 

s 

X 

- 

N 

N 

s 

s 

\ 

\ 

\ 

\ 

\ 

\ 

1 

-1 

H- 

X 

N, 

\ 

N 

-• 

\ 

\ 

\ 

, 

, 

± 

7^ 

X 

" 

\ 

x, 

\ 

| 

\ 

k 

\ 

1 

B 

\  1 

s 

s 

s 

\ 

ss 

\ 

N 

\ 

\ 

\ 

\ 

• 

\ 

1 

\  \\ 

U 

fx 

s 

^ 

s. 

\ 

\ 

.  k 

\  • 

\ 

\ 

\ 

1  i 

. 

X 

X, 

' 

\ 

Sj 

X 

•  . 

\ 

' 

• 

\ 

\ 

\ 

\ 

- 

6N 

^ 

X 

\ 

\ 

• 

S. 

\ 

S, 

^ 

\ 

\ 

' 

\ 

1  \\ 

X 

b 

x 

N 

X 

- 

\ 

N. 

\ 

N 

s    j 

\ 

• 

\ 

; 

J 

\ 

\l\ 

X 

X 

s 

V 

' 

N 

\ 

s 

\ 

\ 

\ 

\ 

^ 

\ 

\  1 

- 

ix 

x, 

s 

X 

s 

"V 

s 

X 

\ 

\ 

•' 

( 

\ 

\ 

1 

,  \\\ 

- 

5> 

> 

X, 

\ 

x, 

^ 

^ 

S  ' 

\ 

• 

\ 

\ 

\ 

N 

\ 

\  \ 

X^ 

X. 

S 

X 

V. 

\ 

\ 

\ 

s 

^ 

v 

\ 

\ 

{  I  \ 

^ 

*X 

- 

X 

- 

N 

X 

X 

S 

•' 

\ 

y 

\ 

\ 

\ 

Y 

A- 

w- 

4 

^ 

•X- 

"X, 

- 

[x 

\^ 

^ 

^ 

X 

"\ 

Xs 

^" 

— 

y 

^~ 

y 

_\ 

MtV 

te~- 

^ 

X 

'"s 

•v 

*N 

x 

. 

> 

\ 

x, 

\ 

\ 

\ 

\i 

3j 

B 

^ 

a 

•••- 

'x 

s^ 

X 

s 

X 

x 

•- 

s 

3 

K   \ 

N^ 

- 

V 

A 

0 

\ 

pr 

n 

ro 

--, 

s 

*•- 

•^ 

^ 

^x 

^ 

-. 

xx 

x 

*\ 

\ 

5 

\ 

\ 

\ 

\^ 

\ 

\ 

M\ 

&    3^ 

™ 

•^v 

^ 

"V 

^ 

x, 

s 
* 

. 

!s 

jj 

\ 

X^ 

-,  ^ 

^ 

s  ^ 

a 

PR 

\ 

1 

^ 

.  

-. 

v 

^ 

, 

x 

.  x 

^  > 

\ 

•-.x 

X 

s^ 

x 

^ 

3 

\ 

\N 

\ 

•  —  . 

•~- 

^, 

•*^, 

L^ 

>- 

s^ 

N^ 

1  5 

s 

\ 

X, 

x 

\ 

, 

s 

\ 

\v 

I  \ 

u 

-- 

-^ 

__^ 

""•• 

-~* 

*^, 

-- 

~^ 

^~ 

•^ 

- 

. 

^> 

^ 

-. 

-xv 

x 

Xs 

\^ 

\ 

' 

\v 

\\ 

2-, 

•^- 

~ 

L^^I 

|^, 

K-- 

^. 

•• 

s 

"X 

• 

x. 

\ 

V 

\ 

EL 

•  —  . 

•  —  - 

— 

__ 

-^- 

•v. 

5 

5 

-^ 

"•  - 

5 

^ 

xs 

x 

t\ 

\ 

\ 

NSKk 

\  \ 

*-^, 

•  —  - 

, 

-~. 

-     - 

._^ 

•  —  . 

"^**. 

^^, 

5= 

^. 

^: 

,^ 

\ 

x 

x, 

^ 

x. 

S 

s- 

s 

\i\ 

SK 

n 

—  - 

— 

—  ^ 

-  —  , 

^~ 

'-- 

& 

*^-* 

**^J 

*x 

^v 

^ 

^ 

3S 

\~  "u 

1. 

-^i 

«= 

___ 

^— 

—  , 

—  — 

1 

-i=< 

-^^: 

-  —  . 

•  — 

^  —  . 
— 

•=-. 

-=3 

._ 

-~_. 

""  '  — 

"-^,i 

- 
=*^ 

>> 
•=c 

^ 

i^ 

-^ 

^ 

!^s. 

•^x*. 

^ 

^ 

l\\ 

• 

f 

mm 

MM 

f 

•Ml 

mm 

1 

MMl 

M. 

{ 

MM 

MM 

+ 

**a 

•Ml 

•  

i 

•  —  , 

MM 

= 

t 

r-». 

•MB 

™*- 

—  = 

! 

—  • 

^=: 

-' 

•  —  , 

t 

^ 


(MM 

--—  ' 

-  —  ^ 
_^> 

MM 

—  • 

•  —  . 
_- 

^~~. 

MM 

.  
^ 

SM. 
"^ 
MM 

^*~ 

*^c= 

MM 

-—  - 

•^•^ 

f 

^~- 

-  —  , 

mm 
•  
• 

J 

^1 

I 

1 

^r^ 

^» 

li 

^*- 

—  — 

^• 

~~ 

—  — 

•^ 

^—  - 

~ 

=-  = 

^f 

-^ 

~ 

S 

r* 

/j 

.4. 

-=" 

—  e 

=rr 



—  — 

— 

-= 

'_ 

~ 

^ 

-/* 

S* 

^ 

'7 

/ 

'     i    / 

/]/ 

" 

- 

- 

^• 

^ 

^ 

' 

/ 

'  / 

/I 

1   * 

^* 

^^ 

" 

s> 

., 

/ 

/ 

/ 

1 

^ 

, 

/ 

^ 

, 

/ 

/•' 

' 

/ 

/ 

'  ,   <- 

.6 

' 

/ 

/ 

/ 

,'- 

{ 

} 

^* 

s 

^ 

| 

- 

4 

/ 

/ 

/ 

-S 

^, 

s 

/ 

/ 

fi 

/ 

o 

^ 

^" 

/ 

S* 

• 

/ 

/ 

' 

-6 

- 

c 

s* 

/ 

•  2 

t~- 

-- 

- 

-7 

~r 

*~" 



'w 

^ 

^ 

^f 

/ 

/ 

/ 

f 

I 

/i/ 

<- 

0 

^ 

'" 

^ 

•^ 

s 

/ 

/ 

/ 

t-'-  n 

^ 

^ 

' 

, 

/ 

/ 

i 

1 

1- 

S 

/ 

' 

/ 

1 

i 

/ 

,, 

/ 

, 

/ 

- 

1 

/ 

/ 

<- 

S\ 

/ 

/ 

f 

, 

i 

/ 

/  1 

1.2 

s 

^ 

/ 

/ 

<. 

/ 

/ 

/ 

/ 

1 

! 

1 

1.4  1.6  1.8 

Loss  in  volts. 


2.  2.4 


.       8.   10. 
Copyright,  1891, 


50    100 


150 


200 


250   300    Feet   400 


500 


8     !    3        § 
2  i  o 

B.  &  S.  Gauge  Numbers. 


00 


<="          o~ 

g  fe 


FEW  LAMPS  AT 


DISTANCES. 


Rule  for  using  the  chart : 

Follow  the  general  direction  of  the  broken  line  and  the  arrows,  from 
one  set  of  diagonals  to  the  next. 

EXAMPLE:  What  size  wire  is  required  for  10  lamps  of  .775  amperes  each,  at  500  feet,  for 
a  loss  of  2  volts? 

SOLUTION  :  Starting  with  the  current  for  1  lamp,  .775  amperes  (see  scale  below  center), 
follow  it  (see  broken  line  and  arrows)  to  the  left,  until  it  intersects  the  diagonal  represent- 
ing 2  volts  loss ;  thence  up  to  the  diagonal  representing  10  lamps  ;  thence  to  the  right  to 
the  diagonal  representing  500  feet,  and  from  here  down  to  the  scale  of  the  circular  mils 
or  gauge  numbers,  on  which  the  reading  is  found  to  be  about  42,000  circular  mils,  or  a 
No.  4  B.  &  S.  wire. 

For  a  more  detailed  explanation,  abbreviated,  aeib<xls;and  general "Jriits,  see  text. 


(Chart  ^B:) 


HERING. 


240  260       300     350  400      600        700        Lamps 


6.       8.   NX 

Copyright,  1891,  1 


10 


70 


9876       5 


2  1  O 

B.  &  S.  Gauge  Numbers. 


MANY  LAMPS  AT  SHORT  DISTANCES. 

5  Rule  for  using  the  chart: 

|  Follow  the  general  direction  of  the  broken  line  and  the  arrows,  from 

^        one  set  of  diagonals  to  the  next. 

Hi,  EXAMPLE  :  What  size  wire  is  required  for  100  lamps  of  .775  amperes  each,  at  50  feet,  for 

•|       a  loss  of  2  volte? 

SOLUTION  :  Starting  with  the  current  for  1  lamp,  .775  amperes  (see  scale  below  center), 
2        follow  it  (see  broken  line  and  arrows)  to  the  left,  until  it  intersects  the  diagonal  represent- 
^       ing  2  volts  loss ;  thence  up  to  the  diagonal  representing  100  lamps  ;  thence  to  the  right  to 
0  <i       the  diagonal  representing  50  feet,  and  from  here  down  to  the  scale  of  the  circular  mils 
cr  gauge  numbers,  on  which  the  reading  is  found  to  be  about  42,000  circular  mils,  or  a 
No.  4,  B.  &  S.  wire. 

For  a  more  detailed  explanation,  abbj-evjated^metho^s  and  ge,ne.ral~bints,  see  text. 

(dwi  icf 

ARL  BERING. 


Copyright,  1891,  b\ 


RL  HERING. 


(Chart  D.) 


DISTRIBUTION  OF  INCANDESCENT  LAMP 
LEADS. 


IN  the  ideal  system  of  wiring  for  incandescent  lamps  (or 
motors)  in  multiple  arc,  there  are  two  requirements,  assuming 
that  the  potential  is  kept  constant  at  the  source :  First,  that  each 
lamp  should  have  the  same  potential  at  its  socket  as  all  the  other 
lamps,  when  all  are  burning  at  once ;  secondly,  that  this  potential 
should  remain  constant  at  each  lamp,  when  the  other  lamps  are 
turned  off.  In  some  cases,  as  for  factories,  street  lights,  store 
lights,  etc.,  only  the  first  requirement  need  be  complied  with ;  in 
other  cases,  as  in  dwellings,  theaters,  etc.,  both  conditions  must 
be  provided  for.  The  second  condition  is  the  one  most  difficult  to 
provide  for,  and  it  necessarily  includes  the  first.  A  number  of 
systems  of  running  the  leads  will  comply  with  the  first  condition, 
but  to  meet  the  second  condition  there  is  only  one  ideal  system. 

In  general,  it  would  be  quite  impracticable  to  comply  strictly 
with  either  of  these  conditions,  and  therefore  a  slight  margin  of 
variation  at  the  different  lamps  is  usually  allowed ;  the  amount  of 
such  allowable  variation,  being  necessarily  different  for  different 
conditions,  must  be  chosen  by  the  judgment  of  the  engineer.  This 
variation  is  due  to  the  different  losses  in  potential  in  the  leads  to 
the  different  lamps.  This  variation  is,  therefore,  not  identical 
with  the  loss  in  the  leads,  but  it  is  the  differences  between  these 
losses  when  the  losses  are  not  precisely  the  same  to  all  lamps. 

The  amount  of  wire  used  increases  very  rapidly  as  the  allow- 
able loss  is  diminished ;  for  a  1  per  cent,  loss,  for  instance,  the 
amount  of  wire  by  weight  is  double  what  it  would  be  for  a  2  per 
cent.  loss.  On  the  other  hand,  if  the  lamps  must  be  capable  of 
being  turned  off  one  by  one,  the  life  of  the  lamps  in  the  general 
systems  will  diminish  rapidly  as  this  allowable  loss  is  increased, 
because  the  unavoidable  differences  between  the  losses  to  different 
lamps,  that  is,  the  variation,  increases.  It  is,  therefore,  a  choice 
between  two  evils.  As  the  conditions  are  quite  different  in  the 

(9) 


10  WIRING   COMPUTER. 

case  when  the  lamps  may  be  turned  off  one  by  one,  than  when 
they  always  burn  together,  the  two  cases  must  be  considered  sepa- 
rately and  should  not  be  confounded  with  each  other ;  the  former, 
of  course,  includes  the  latter,  and  is,  therefore,  merely  an  addi- 
tional condition  to  the  latter. 

The  case  in  which  all  the  lamps  are  either  burning  or  turned 
off  together,  is  by  far  the  simpler  of  the  two.  In  the  simple  case 
shown' in  Fig.  1,  the  difference  between  the  potential  at  the  nearest 

FIG.  1. 


000000000000 

lamp  and  that  at  the  farthest,  is  merely  the  amount  lost  in  the 
length  of  wire  between  the  two  lamps,  and  it  is  entirely  independ- 
ent of  the  amount  lost  between  the  dynamo  (or  center  of  distri- 
bution) and  the  first  lamp ;  this  latter  loss  may,  therefore,  be  made 
as  great  as  desired,  as  far  as  the  lamps  are  concerned.  In  this 
case,  therefore,  the  loss  from  the  dynamo  to  the  first  lamp  may  be 
made  anything  that  is  desired,  but  the  wire  between  the  first  and 
last  lamp  must  be  so  large  that  the  loss  on  that  portion  does  not 
exceed  the  allowable  variation  for  the  lamps,  say  about  1  percent.; 
or  at  most,  2  per  cent.  If  this  portion  of  the  circuit  is  so  long 
that  it  would  require  a  very  large  wire,  then  the  lamps  are  often 
divided  into  two  or  more  groups,  as  shown  in  Fig.  2,  each  group 


i 


oooooooooooo 


being  supplied  or  fed  by  a  separate  set  of  leads  ;  these  two  sepa- 
rate sets  of  leads  must  then  be  calculated  for  the  same  loss  as 
before  between  the  dynamo  and  the  lamps,  thus  requiring  the 
longer  ones  to  be  much  thicker  than  the  shorter  ones,  as  shown. 
The  choice  between  the  dispositions  shown  in  Figs.  1  and  2  de- 
pends entirely  on  whether  the  wire  between  the  first  and  the  last 
lamp  must  be  so  thick,  owing  to  the  allowable  difference  between 
the  lamps,  that  it  would  be  cheaper  to  divide  the  leads  to  dynamo 
into  two  parts ;  this  can  be  determined  only  by  calculating  both 
cases.  In  Fig.  1  it  might,  under  special  circumstances,  be  quite 


DISTRIBUTION   OF   INCANDESCENT   LAMP   LEADS.  11 

rational  to  connect  the  lamps  by  a  much  thicker  wire  than  that 
leading  to  the  dynamo,  even  though  the  latter  carries  a  greater 
current.  The  disposition  shown  in  Fig.  2,  of  running  separate 
sets  of  leads  to  different  groups  of  lamps,  applies  equally  well  to 
groups  of  lamps  in  different  directions  from  the  center  of  distri- 
bution, and  in  this  sense  it  is  one  of  the  most  frequent  and  best 
systems  of  distribution. 

Another  system,  but  applicable  only  in  special  cases,  is  that 
shown  in  Fig.  3,  in  which  the  two  leads  from  the  dynamo  divide, 

FIG.  3. 


one  going  in  one  direction  around  a  rectangle,  and  the  other  going 
in  the  reverse  direction.  No  matter  what  the  loss  or  the  size  of 
the  wire,  all  the  lamps  between  this  pair  of  leads  will  have  the 
same  potential,  provided  the  positive  and  negative  leads  are  both 
of  the  same  size,  and  provided  all  the  lamps  are  turned  on  and 
off  together ;  if  the  lamps  are  turned  off  one  by  one,  the  potential 
will  no  longer  be  constant. 

To  recapitulate,  it  will  be  seen  that  when  the  lamps  of  a  group 
are  all  turned  on  or  off  together,  and  not  individually,  the  distri- 
bution is  simple,  requiring  only  that  the  difference  between  the 
potential  at  the  nearest  and  the  farthest  lamp  on  the  same  leads 
shall  not  exceed  the  allowable  variation  of  1,  2  or  even  3  per  cent, 
(in  which  case  the  lamps  are  entirely  independent  of  the  loss  be- 
tween them  and  the  dynamo  or  center  of  distribution),  and  that  if 
there  are  a  number  of  such  groups  connected  to  the  same  dynamo 
or  center,  the  loss  from  dynamo  to  lamp  must  be  the  same  for  each 
group.  In  the  latter  case  the  groups  will  be  entirely  independent 
of  each  other,  and  may  be  turned  off  or  on  as  individual  groups, 
provided  their  leads  do  not  join  those  of  any  other  group  on  their 
way  to  the  dynamo.  In  other  words,  groups  having  independent 
connections  to  the  dynamo  are  independent  of  each  other,  and 


12  WIRING   COMPUTER. 

may  be  turned  off  or  on  as  groups.  It  is  assumed,  of  course,  that 
the  dynamo  is  self-regulating. 

Taking  up  the  other  case,  in  which  the  individual  lamps  are  to 
be  turned  off  and  on,  the  problem  is  quite  a  different  one.  Refer- 
ring again  to  Fig.  1,  the  loss  of  potential  from  each  lamp  to  the 
dynamo  or  source,  depends  on  the  total  current  in  the  common 
leads  and  on  the  resistance  of  these  leads ;  these  losses,  therefore, 
remain  constant  only  as  long  as  the  total  current  is  constant ;  if 
one  lamp  is  turned  off,  the  total  current  becomes  less,  and,  there- 
fore, the  loss  to  each  remaining  lamp  becomes  less,  and  vice  versa. 
Finally,  if  all  but  one  of  the  many  lamps  are  turned  off,  the  loss 
in  the  leads  will  be  very  small,  and,  therefore,  the  potential  at  the 
last  remaining  lamp  will  be  increased  accordingly.  Each  individ- 
ual lamp  is,  therefore,  dependent  not  only  on  the  others,  but  also 
on  the  total  loss  of  potential  between  it  and  the  dynamo.  It  is  in 
the  latter  feature  that  this  case  differs  entirely  from  the  first  case 
described  above,  in  which  they  are  all  turned  off  or  on  together. 
For  independent  lights  the  loss  between  them  and  the  dynamo 
must,  therefore,  be  made  as  small  as  practicable,  as  it  affects  the 
steadiness  and  life  of  the  lamps.  For  this  reason  it  requires,  in 
general,  relatively  thicker  wire  for  independent  lamps  than  for 
groups,  provided  the  distance  to  the  dynamo  is  sufficiently  great 
to  make  a  difference. 

Suppose,  in  Fig.  1,  there  are  100  lamps  and  the  loss  from  the 
dynamo  to  the  first  lamp  is  four  volts  when  all  are  burning ;  then 
if  all  but  one  are  turned  off,  the  voltage  of  that  one  will  be  about 
four  volts  in  excess  of  what  it  should  be.  In  order  to  save  the 
lamps  from  part  of  this  strain,  the  voltage  of  the  dynamo  may  be 
so  chosen  that  when  all  are  burning  they  will  be  two  volts  below 
the  normal,  and  when  only  one  is  burning  it  will  be  two  volts 
above,  the  difference  remaining,  as  before,  four  volts.  If,  as  in  a 
dwelling,  the  full  number  of  lights  burning  is  the  exception,  and 
a  few  lights  the  rule,  then  the  potential  at  the  dynamos  may  be 
chosen  so  that  it  is  the  proper  amount  at  the  lamps  when  the  aver- 
age number  is  turned  on. 

As  the  potential  at  the  lamp  depends  on  the  total  current  in 
the  leads,  it  follows  that  the  ideally  perfect  system  of  independent 
lamps  is  to  have  a  separate  pair  of  leads  for  each  lamp  back  to 
the  dynamo  (or  center  of  distribution).  Each  pair  of  leads  is  then 
calculated  so  as  to  have  the  required  loss  for  its  lamp.  Such  an 


DISTRIBUTION   OF   INCANDESCENT   LAMP   LEADS.  13 

ideal  system  is,  however,  not  practicable,  as  a  rule,  but  the  general 
rule  may  be  laid  down,  that  the  nearer  a  system  approaches  to 
this  ideal,  the  better  it  is.  For  instance,  comparing  Figs.  1  and  2, 
in  each  of  which  there  are  twelve  lamps,  the  second  approaches 
more  nearly  to  the  perfect  system,  and  the  lamps  in  Fig.  2  are 
subjected  to  only  half  as  great  a  variation *in  potential  as  those  in 
Fig.  1,  when  all  but  one  are  turned  off.  It  follows  from  this  rule 
that  the  distribution  is  better,  the  more  a  circuit  is  branched,  the 
nearer  such  branch  connections  are  to  the  dynamo,  and  the  larger 
the  number  of  independent  leads  to  the  dynamo.  Such  distribu- 
tion is  better,  not  only  because  the  lamps  are  subjected  to  less 
variation  of  potential,  but  for  the  same  allowable  variation  of,  say 
2  per  cent,  at  the  lamp,  the  total  loss  from  the  dynamo  to  the 
lamps  may  be  chosen  much  greater  than  in  other  systems  and 
thereby  saving  wire,  for  it  is  evident  that  in  the  ideal  system  the 
loss  from  the  dynamo  to  the  lamps  may  be  made  anything  de- 
sired, without  making  the  lamps  dependent  on  each  other ;  their 
dependence  on  each  other  varies  with  and  is  proportioned  to,  the 
number  of  lamps  on  one  wire,  and  the  distance  from  the  dynamo 
to  the  junction  of  their  individual  wires. 

It  is  sometimes  thought  that  the  ideal  system  may  be  carried 
out  by  calculating  the  leads  to  each  lamp  or  groups  of  lamps  sep- 
arately and  then  bunching  all  the  wires  running  parallel  into  one 
common  wire  having  a  cross-section  equal  to  the  sum  of  all  the 
smaller  wires  combined.  But  this  is  an  error  and  may  result  in  a 
worse  distribution  than  if  it  had  been  calculated  on  the  usual 
plan.  As  soon  as  two  wires  are  metallically  connected  they  become 
one  and  the  same  wire  from  there  to  the  dynamo. 

To  recapitulate :  When  the  lamps  are  to  be  cut  off  independ- 
ently they  are  dependent  on  each  other  and  on  the  loss  of  potential 
between  them  and  the  dynamo  in  so  far  as  they  are  connected  to 
common  leads.  The  leads  should  therefore  be  split  up  as  much  as 
practicable,  and  the  total  loss  should  be  divided  so  as  to  have  the 
greater  part  in  the  small  individual  branch  wires,  and  the  smaller 
part  in  the  larger  main  wires. 

To  calculate  the  wires  for  a  building  with  independent  lamps, 
lay  them  out  so  as  to  approach  as  much  as  practicable  to  the 
best  distribution  as  described  above,  making  common  mains  as 
short  as  possible,  and  individual  branch  wires  as  great  a  propor- 
tion of  the  whole  as  possible;  then  determine  on  the  total  loss,  for 


14  WIRING   COMPUTER. 

instance,  four  volts,  and  divide  it  amongst  the  leads  so  as  to  have 
as  small  a  part  as  practicable  (say  one  volt)  on  the  common  main, 
and  the  other  part  (three  volts)  again  divided,  if  necessary,  on  the 
distributing  branch  wires.  Calculate  the  size  of  each  wire  from 
the  number  of  lamps  supplied  by  it,  and  from  this  portion  of  the 
total  loss  allowed  for  that  part  of  the  whole  lead.  The  lamps  will 
then  be  dependent  on  each  other  only  in  so  far  as  they  are  on 
common  wires,  and  to  an  amount  that  other  lamps  effect  the  loss 
only  on  this  common  wire. 

To  illustrate  some  of  the  points  mentioned  above  by  an  actual 
(exaggerated)  case,  suppose  the  leads  for  four  lamps,  a,  6,  c,  d,  Fig.  4, 
be  subdivided  as  shown,  and  suppose  the  total  loss  of  8  volts  be 

FIG.  4. 


1  volt 


^ 


* 


oc 


FIG.  5. 


divided  into  5,  2  and  1,  as  indicated,  on  the  separate  mains  and 
branches ;  the  relative  distances  being  in  the  proportions  of  the 
diagram.  The  loss  is  proportionately  small  on  the  common  mains 
and  large  on  the  individual  branches.  Now,  taking  any  one  lamp, 
as  a,  its  voltage  will  be  increased  as  follows :  With  b  turned  off, 
1J  volt ;  with  c  or  d  turned  off,  J  volt ;  with  c  and  d  both  turned 
off,  J  volt ;  with  6,  c  and  d  turned  off,  If  volt.  This  shows  that 
lamp  a  is  dependent  on  the  others  in  proportion  as  it  is  on  com- 
mon mains  with  them,  and  on  the  loss  of  volts  on  the  common 
mains,  which  is  small  in  this  case. 

Now,  for  the  sake  of  comparison,  let  the  four  lamps  be  sup- 
plied by  a  single  pair  of  mains,  as  in  Fig.  5,  with  the  same  loss  of 
8  volts.  Turning  off  one  lamp  increases  the  voltage  of  the  others 
2  volts ;  with  two  lamps  turned  off,  4  volts ;  and  with  three  lamps 
off,  6  volts.  This  shows  how  very  great  the  difference  is,  namely, 
a  maximum  of  6  volts  in  Fig.  5,  as  compared  to  If  volts  in  Fig.  4. 


DISTRIBUTION   OF  INCANDESCENT  LAMP   LEADS.  15 

The  weight  of  wire  in  Fig.  4  is  only  slightly  higher,  namely,  as 
23  to  20.  If  now  the  wire  in  Fig  5  be  made  larger,  so  as  to  have 
the  same  maximum  variation  in  volts  as  in  Fig.  4,  namely,  If  volt, 
the  total  loss  would  have  to  be  2  volts,  and  this  would  increase 
the  weight  of  wire  to  about  three  times  that  in  Fig.  4,  showing 
the  advantage  in  subdividing  the  leads,  aside  from  the  fact  that 
Fig.  4  is  a  distribution  (as  the  lamps  might  just  as  well  be  at  the 
same  distance  in  different  directions),  while  that  in  Fig.  5  is  not. 
The  actual  figures  will,  of  course,  vary  greatly  under  different  cir- 
cumstances, and  no  general  statement  can  be  made  regarding  the 
amount  of  gain. 

In  referring  to  the  dynamo  in  the  above  deductions  it  was 
understood  to  mean  the  place  from  which  distribution  begins, 
that  is,  the  center  of  distribution,  or  the  common  point  at  which 
the  potential  is  kept  constant.  In  wiring  large  buildings  or  spaces 
it  is  usual  to  run  a  pair  of  large  mains  to  a  central  point  from 
which  distribution  begins;  this  pair  of  mains,  provided  it  is  the 
only  one  from  the  dynamo,  is  not  included  in  the  above  discus- 
sion, as  it  is  supposed  that  the  dynamo  is  so  regulated  as  to  keep 
a  constant  potential  at  the  far  ends  of  this  pair  of  mains,  that  is, 
at  the  center  of  distribution ;  if  the  dynamo  does  not  do  this,  or 
if  there  is  more  than  one  pair  of  such  mains,  then  it  brings  the 
center  of  distribution  back  to  the  dynamo,  thus  making  these 
mains  part  of  the  distribution. 

A  great  mistake  is  often  made  in  supposing  that  a  dynamo  can 
keep  the  potential  constant  at  more  than  one  distant  center  of  dis- 
tribution, without  special  apparatus  at  the  dynamo.  This  refers, 
of  course,  to  a  system  of  independent  lamps.  Suppose  all  lamps 
are  turned  on  at  one  center,  and  only  one  lamp  is  on  at  the  other, 
this  lamp  will  be  run  too  high,  as  the  dynamo  must  be  kept  at  the 
same  high  potential  on  account  of  the  lamps  on  the  other  center. 
It  can  be  accomplished  only  in  one  of  two  ways,  first,  approxi- 
mately, by  making  the  loss  on  the  mains  very  small ;  secondly, 
by  regulators  in  each  of  the  original  branches  from  the  dynamo. 

It  has  been  suggested  to  put  lower  voltage  lamps  at  the  most 
distant  centers,  and  higher  voltage  lamps  at  the  nearer  ones,  on 
account  of  the  greater  loss  in  the  longer  mains.  It  is  a  question 
Whether  this  is  practicable,  for  a  number  of  reasons.  A  lower  volt 
lamp  requires  a  greater  current  and,  for  this  reason  alone,  a  larger 
wire.  It  is  not  a  good  practice  to  have  lamps  of  differing  voltages  in 


16  WIRING   COMPUTER. 

stock  for  one  and  the  same  building  or  installation,  unless  there  is 
a  reliable  person  to  take  charge  of  their  proper  placing. 

In  the  three-wire  system  there  are  practically  two  lamps  in 
series,  and,  therefore,  the  current  need  be  sent  out  and  back  only 
once  for  every  two  lamps ;  this  requires  but  half  the  wire  (in  cross- 
section)  otherwise  necessary  for  the  same  number  of  lamps.  Fur- 
thermore, the  loss  of  volts  is  divided  between  two  lamps,  and  it 
can  therefore  be  made  twice  as  great  as  in  the  simple  system ;  this 
halves  the  quantity  of  wire  again,  making  the  total  one-quarter  as 
great  as  for  the  two-wire  system.  To  carry  the  current  for  any 
lamp  which  may  not  at  the  time  have  another  in  series  with  it,  a 
third  or  neutral  wire  is  laid,  which,  in  wiring  buildings,  is  usually 
made  the  same  size  as  the  other  two ;  this  increases  the  wire  by  a 
half,  making  the  total  three-eighths  of  that  required  for  the  sim- 
ple system.  To  calculate  the  leads  for  the  three-wire  system,  pro- 
ceed as  in  the  simple  system  and  divide  the  cross-section  obtained 
by  four,  using  three  wires  of  this  cross-section.  The  same  result 
would,  of  course,  be  obtained  by  using  one-quarter  the  number  of 
lamps,  or  one-quarter  the  distance,  or  four  times  the  loss. 


FUSIBLE  CUT-OUTS. 


The  general  principle  of  safety  or  fusible  cut-outs  is  that  they 
protect  from  a  dangerous  excess  of  current  those  wires  which  are 
beyond  them,  as  distinguished  from  the  wires  between  them  and 
the  dynamo,  which  are  not  protected  by  the  fuses.  They  should 
therefore  always  be  placed  at  the  beginning  of  a  wire  (that  is,  at 
the  end  toward  the  dynamo)  and  not  at  the  lamp  end.  Further- 
more, they  should  be  made  so  small  that  they  protect  the  smallest 
wire  lying  beyond  them  up  to  the  next  fuse ;  this  is  not  infre- 
quently overlooked,  and  may  be  a  source  of  great  danger.  A  thick 
wire  is  sometimes  protected  by  a  large  fuse,  because  it  is  a  thick 
wire,  notwithstanding  that  a  small  wire  is  attached  to  it,  unfused ', 
there  is  always  great  damage  in  such  cases.  It  follows,  there- 
fore, that  wherever  the  wire  changes  its  size,  a  fuse  should  be 
placed,  unless  the  fuse  preceding  it  is  small  enough  for  the  small- 
est wire  beyond  it.  In  general,  therefore,  a  fuse  should  be  placed 
at  the  beginning  of  every  branch  circuit,  except  as  explained. 

If  only  one  side  of  a  circuit  is  protected  by  fuses,  the  building 
is  not  completely  protected,  as  there  are  possible  cases  in  which  a 
wire  might  become  overheated,  as,  for  instance,  when  a  heavily- 
fused  wire  and  a  light  unfused  wire  are  both  grounded  or  in  con- 
tact. Fuses  should,  therefore,  always  be  "  double-pole." 

It  has  been  suggested  to  make  the  fuses  of  copper  wire  of  a 
certain  number  of  sizes  smaller  than  the  size  of  the  wire  to  be  pro- 
tected by  it.  This  would  be  a  very  good  general  rule  and  guide, 
but  the  temperature  of  the  fused  copper  is  so  very  much  higher 
than  that  of  lead  alloys,  that  there  would  be  danger  of  fire  caused 
by  scattering  of  this  melted  copper. 

Fuses  should  be  marked  with  the  current  at  which  they  will 
fuse,  but  as  such  marks  are  sometimes  very  unreliable,  even  with 
fuses  sold  by  otherwise  reliable  companies,  a  careful  engineer  will 
always  test  a  sample  fuse  before  using  them.  Some  fuses  are 
marked  with  the  number  of  lamps  normally  supplied  by  them, 
others  with  amperes,  others  with  the  fusing  current,  etc.;  unless  it 
is  known  what  such  marks  mean,  it  is  not  safe  to  trust  them. 

(17) 


WIRING  FORMULAE.    THEIR  DEDUCTION 
AND  USE. 


When  a  current  passes  through  a  wire  there  is  a  gradual  loss 
of  voltage  along  the  whole  length  of  the  wire.  This  loss,  from 
Ohm's  law,  is  equal  to  the  product  of  the  current  and  the  resist- 
ance, that  is, 

E  =  CR 
Now,  the  resistance  of  a  wire  is  equal  to 

R=  L  10.611 
d2 

in  which  R  is  in  legal  ohms,  at  about  75°  to  80°  F. ;  L  is  the  length 
of  the  wire  in  feet,  d  is  the  diameter  in  mils  or  d2  the  cross-section 
in  circular  mils. 

From  these  two  formulae  it  follows  that 
„     10.61  C  L 
E  =     -dT- 

from  which  the  loss  in  volts  can  be  determined  for  any  current, 
length  and  diameter  of  wire.  As  the  circuit  is  usually  a  loop  or 
return  circuit,  it  is  simpler  to  use  the  distance,  represented  by  D 
which  is  equal  to  ^  L.  Furthermore,  as  the  loss  is  usually  known, 
while  the  diameter  is  that  which  is  required,  the  formula  reduces 
to  the  form 

j>2_21.21  CD 

E 

in  which  D  is  the  distance  in  feet  from  the  dynamo  to  the  lamps 
or  motor,  and  E  is  the  loss  in  volts. 

For  arc  light  circuits  this  formula  is  in  its  simplest  form,  and 
for  motor  circuits  also,  after  having  first  determined  the  current  (7, 
which  is  equal  to  746  times  the  horse-power  divided  by  the  volt- 
age of  the  motor,  or  which  may  be  found  from  the  tables  of  horse- 
power equivalents  in  the  back  of  this  book,  see  pages  36  and  37. 

1  This  constant  is  in  accordance  with  the  new  Matthiessen  standard  suggested  by  the  Com- 
mittee of  the  American  Institute  of  Electrical  Engineers. 

(18) 


WIRING   FORMULA.  19 

For  incandescent  lighting  this  formula  may  be  still  further 
simplified  by  substituting  the  number  of  lamps  n  for  the  current 
O,  in  which  case  it  is  necessary  to  introduce  the  constant  c,  which 
is  the  current  required  by  one  lamp.  This  is  usually  multiplied 
once  for  all  by  21.21,  giving  what  is  generally  termed  the  "con- 
stant "  for  calculating  the  leads  for  that  lamp.  The  formula  then 
becomes 


in  which  the  quantity  in  parentheses  is  the  "  constant  "  calculated 
once  for  all.  This  constant  is  then  divided  by  the  actual  loss  in 
volts,  E  (not  in  per  cent.),  which  gives  a  new  constant,  but  for  that 
loss  only. 

The  calculation  is  therefore  as  follows  :  Multiply  the  number  of 
lamps  by  the  distance  in  feet  and  by  the  constant  (which  constant  has 
first  been  divided  by  the  loss  in  volts).  The  answer  is  the  cross- 
section  in  circular  mils.  From  a  table  (see  page  23)  find  what 
gauge  number  this  corresponds  to,  or  from  a  table  of  squares  or 
square  roots  find  the  diameter  in  mils  of  which  this  is  the  square. 

If  lamps  of  different  candle-power  (and  therefore  of  different 
currents)  are  used  together,  it  is  best  to  reduce  them  all  to  thd 
equivalent  in  one  size,  or  else  find  the  total  current  in  amperes, 
and  use  the  original  formulae  in  which  the  current  is  used  instead 
of  the  number  of  lamps. 

The  loss  is  often  given  in  per  cent,  instead  of  in  volts.  To  find 
what  this  is  in  volts,  it  is  necessary  merely  to  multiply  the  voltage  of 
the  lamp,  V,  by  the  per  cent,  (in  whole  numbers,  thus,  2  per  cent.) 
and  divide  by  100.  Or  to  bring  this  all  into  the  formula  gives 


in  which  V  is  the  voltage  of  the  lamps,  and  %  is  the  loss  in  per 
cent,  (in  units,  thus,  2). 

Instead  of  giving  the  cross-section  in  circular  mils,  namely,  d\ 
the  formula  might  be  made  to  give  it  in  square  mils,  but  the  very 
good  practice  of  using  circular  mils  instead  of  square  mils  has 
become  so  universal  and  is  so  much  simpler,  that  the  other  is  no 
longer  to  be  recommended.  To  change  the  above  formulae  so  as 
to  give  the  answer  in  square  mils  instead  of  circular  mils,  multi- 
ply the  numerical  constant  by  .7854,  and  change  d*  to  a. 

From  the  above  explanation  regarding  the  "  constant  "  anyone 


20  WIRING   COMPUTER. 

will  be  able  to  calculate  the  constant  for  any  make  of  lamp.  It 
is  always  best  to  calculate  this,  unless  one  is  very  sure  what  the 
constant  given  by  the  makers  means.  To  determine  the  constant 
it  is  necessary  to  have  the  current  required  for  one  lamp ;  when- 
ever possible,  it  is  best  to  measure  this  one's  self  for  a  batch  of 
10  or  100  lamps,  as  the  figures  given  by  the  makers  are  sometimes 
considerably  below  their  true  values. 


TABLES. 


PAGE 

Tables  of  Wire  Gauges 23 

Table  of  Compounded  Wires  of  Large  Cross  Section „  ....  28 

Table  of  the  Weight  and  Resistance  of  Copper  Wire 30 

Table  of  Temperature  Corrections  for  Copper  Wire 32 

Weight  of  Insulated  Wire  for  Wiring 33 

Table  of  Heating  Limits  or  Maximum  Safe  Carrying  Capacity  of 

Insulated  Wires «...  34 

Table  of  Horse  Power  Equivalents .  ,   .  35 

Wiring  Tables 1 • .   „ 38 


(21) 


TABLES  OF  WIRE  GAUGES.  23 


TABLES  OF  WIRE  GAUGES. 

Tables  giving  the  diameters  and  cross-sections  of  different  wire- 
gauge  numbers  are  usually  given  separately,  or,  if  together,  they 
usually  give  approximate  equivalents  only.  As  the  latter  is  often 
insufficient,  the  accompanying  table  has  been  arranged  to  give  in  the 
order  of  their  size  all  the  values  for  each  of  the  principal  Ameri- 
can and  European  gauges.  All  the  approximate  equivalents  may, 
therefore,  be  readily  found  by  mere  inspection,  while  the  degree  of 
approximation  may  be  seen  directly  from  their  cross-sections  or 
diameters.  It  therefore  forms  a  complete  and  combined  set  of  all 
the  gauges  used  in  practice. 

The  tables  usually  published  often  give  only  approximate  diam- 
eters and  cross-sections,  and  some  of  them  contain  a  number  of 
errors.  The  accompanying  table  has,  therefore,  been  calculated 
from  the  original  correct  data.  It  may  not  be  generally  known 
that  the  tables  of  B.  &  S.  gauges,  as  usually  published,  contain  a 
number  of  errors  which  were  apparently  copied  from  an  incorrect 
original,  and  have  been  acknowledged  to  be  errors  by  the  origi- 
nators. The  corrected  values  have  been  used  in  this  table. 

In  connection  with  the  B.  &  S.  gauge,  it  may  be  added  here 
that  it  follows  a  regular  law,  each  cross-section  being  a -certain  per 
cent,  smaller  than  the  one  before.  It  may  not  be  generally  known 
that  with  every  three  sizes  the  cross-section  is  doubled  approxi- 
mately. Thus,  No.  4,  for  instance,  is  very  nearly  twice  as  large  in 
cross-section  as  No.  7  and  half  as  large  as  No.  1.  The  error  is 
only  one-quarter  of  1  per  cent.  This  rule  applies  to  the  whole 
range  of  the  gauge. 

The  accompanying  table  may  be  used  also  for  converting  diam- 
eters into  areas,  millimetres  into  mils,  diameters  of  the  one  into 
areas  of  the  other  units,  etc.,  and  vice  versa. 


24 


WIRING   COMPUTER. 


TABLES  OF  WIRE  GAUGES. 

American  and  European. 

WITH  CROSS-SECTIONS  AND  DIAMETERS 
Arranged  for  Comparison  and  Reduction. 


GAUGES  AND  SCALES. 

CROSS-SECTION. 

DIAMETER. 

§ 
•8 

1 

fi 

1 

"  i. 
* 

MILLIMETER  SCALE. 
(Diam.  in  Millimeters.) 

DECIMAL  SCALE. 
(Diam.  in  Mils.) 

EDISON  GAUGE. 

BIRMINGHAM,  or  Stubs 
(Holzapffel)  or  Old  English 
Standard  Gauge.  B.W.G. 

NEW  BRITISH,  or  Standard 
Gauge  (March  1st,  1884). 

American  or 
B.  &  S.  GAUGE. 

CIRCULAR  MILS.  (=-  d«) 
(1  Circular  Mil  —  .7854 
Square  Mils.) 

SQUARE  MILS. 
(1  Sq.  Inch  =  1,000,000. 
Sq.  Mils.) 

SQUARE  MILLIMETERS. 
(1  Sq.  m.  m.  —  1550.1 
Sq.  Mils). 

MILLIMETERS. 
(1  m.  m.  =-  39.3708  Mils.) 

MILS.  (<=d). 
(1  Inch  —  1,000.  Mils.) 

II. 

in. 

IV. 

v. 

VI. 

VII. 

VIII. 

IX. 

506.69 
285.01 
197.93 
182.41 
172.28 

"miT 

152.01 
141.88 
131.74 
126.68 

XI. 

XII. 

1000 
750 
625 

1  OOO  OOO. 
562  5OO. 
39O625. 
36OOOO. 
34O  OO6. 

785398. 
441  786. 
3O6  796. 
282  743. 
267  O4O. 

25.400 
19.050 
15.875 
15.240 
14.810 

1OOO.O 
75O.OO 
625.00 
600.00 
583.10 

360 
340 

320 
300 
280 
260 

32OOO5. 
3OOOO8. 
28OO1O. 
26OOO8. 
25OOOO. 

251  332. 
235626. 
21992O. 
2O421O. 
196  35O. 

14.365 
13.912 
13.440 
12.952 
12.700 
"12^43- 
11.914 
11.785 
11.684 
11.531 

565.69 
547.73 
529.16 
509.91 
500.00 

JL 

5OO 

7/0 

.... 

240 
220 

24OOO2. 
22OOO8. 
215296. 
211  6OO. 
206116. 

188497. 
172794. 
169  O93. 
166190. 
161883. 

121.61 
111.48 
109.09 
107.22 
104.44 

489.90 
469.05 
464.00 
46O.OO 
454.OO 

6/0 

OOOO 

oooo 

45O 

2OO 

2O2  5OO. 
2COOO6. 
191  4O6. 
190000. 
186624. 

159O43. 
157084. 
150330. 
149226. 
146574. 

102.61 
101.34 
96.98 
96.27 
94.56 

11.430 
11.359 
11.113 
11.071 
10.972 

450.00 
447.22 
437.  5O 
435.89 
432.  OO 

Ks 

19O 

5/0 

425 

18O 

ooo 

180625. 
180005. 
170008. 
167805. 
16OOOO. 
155006. 
150001. 
1444OO. 
14O625. 
14OOO3. 
"1398937 
138384. 
133079. 
13OOO4. 
125555. 

141863. 
141376. 
133524. 
131  79O. 
125664. 

91.61 
91.21 
86.14 
85.03 
81.07 

10.795 
10.776 
10.473 
10.405 
10.160 

425.00 
424.27 
412.32 
4O9.64 
4OO.OO 

17O 

000 

400 

16O 

OOOO 

1O 

15O 

121  74O. 
117811. 
113411. 
110450. 
109958. 

78.54 
76.00 
73.17 
71.25 
70.94 

10.000 
9.837 
9.652 
9.525 
9.504 

393.71 
387.30 
380.00 
375.  OO 
374.17 

oo 

% 

375 

14O 

:»  fi 

OOO 

'   00  ' 

1O9858. 
108687. 
104518. 
1O2  1O5. 
98  588. 

70.88 
70.12 
67.43 
65.87 
63.62 

9.500 
9.448 
9.266 
9.158 
9.000 

374.02 
372.00 
364.80 
360.56 
354.34 
350.00 
348.00 
346.42 
343.75 
34O.OO 

ISO 

9. 

35O 

OO 

122  500. 
121  104. 
120007. 
118  164. 
1156OO. 

96211. 
95115. 
94253. 
92810. 
9O792. 

62.07 
61.37 
60.81 
59.87 
58.57 

8.890 
8.839 
8.799 
8.731 
8.636 

12O 

& 

340 

0 

^  f> 

no 

111992. 
11OOO5. 
1O5625. 
1O5534. 
1O4976. 
100001. 
992O4. 
97656. 
95OO5. 
9O  OOO. 

87968. 
86398. 
82958. 
82887. 
82  448. 
78541. 
77914. 
76  699. 
74617. 
70686. 

56.75 
55.74 
53.52 
53.47 
53.19 

8.500 
8.424 
8.255 
8.2-51 
8.229 

334.65 
331.67 
325.00 
324.86 
324.00 

325 

o 

0 

R 

1OO 

50.67 
50.27 
49.48 
48.14 
45.60 

8.032 
8.000 
7.937 
7.829 
7.620 

316.23 
314.97 
312.50 
308.23 
300.00 

*A* 

95 

3OO 

9O 

1 

1 

'l.h 

85 

87191. 
85001. 
83  694. 
80656. 
80  004. 

68  479. 
66  76O. 
65732. 
63347. 
62835. 

44.18 
43.07 
42.41 
40.87 
40.54 

7.500 
7.405 
7.348 
7.213 
7.184 

295.28 
291.55 
289.  3O 
284.OO 
282.85 

1 

2 

80 

£ 

2 

79  1O2. 
76  176. 
75953. 
75625. 
75  OO5. 

62  ISO. 
59828. 
59653. 
5939O. 
68  9O8. 

40.80 
38.59 
38.48 
38.32 
38.00 

7.144 
7.010 
7.000 
6.985 
1      6.956 

281.25 
276.OO 
275.  6O 
275.OO 
273.87 

7 

275 

75 

Copyright,  1891,  by  CARL  BERING. 


TABLES   OF   WIRE   GAUGES. 


25 


GAUGES  AND  SCALES. 

CROSS-SECTION. 

DIAMETER. 

£ 

Millimeters. 

1 

! 

0 
£ 
M 

British. 

02 

*5 
« 

fg 

!a 

* 

Square 
Millimeters. 

Millimeters. 

| 

I. 

II. 

III. 

IV. 

V. 

VI. 

VII. 

VIII. 

IX. 

~549807 
52  685. 
52  128. 
51  436. 
51  O55. 

X. 

-35.47 
33.99 
33.63 
33.18 
32.94 

XI. 

XII. 

7O 

70003. 
67O81. 
66373. 
65  49O. 
65OO5. 
63  5O4. 
62  5OO. 
6OOO1. 
56.644. 
558O2. 

6.720 
6.578 
6.544 
6.500 
6.476 

264.58 
259.  OO 
257.63 
255.91 
254.96 

3 

2 

6.5 

65. 

y* 

25O 

3 

49876. 
49  O87. 
47  124. 
44488. 
43827. 

32.18 
31.67 
30.40 
28.70 
28.27 

6.401 
6.350 
6.222 
6.045 
6.000 
"5.957" 
5.952 
5.893 
5.827 
5.715 

252.  OO 
250.00 
244.95 
238.00 
236.23 

6O 

4 

6. 

it 

55 

55  OO4. 
54932. 
53824. 
52  634. 
50625.  • 

43  2OO. 
43  143. 
42273. 
41  339. 
39761. 

27.87 
27.83 
27.27 
26.67 
25.65 

234.53 
234.38 
232.  OO 
229.42 
225.  OO 

4 

3 

225 

5O 

5 

5OOO1. 
48  4OO. 
47852. 
46889. 
45  OO3. 

39271. 
38O13. 
3758O. 
36827. 
35346. 

25.34 
24.52 
24.25 
23.76 
22.80 
"22.7T 
21.15 
20.91 
20.88 
20.27 

5.680 
5.588 
5.556 
5.500 
5.388 

223.61 
22O.OO 
218.75 
216.54 
212.14 

& 

5.6 

45 





5 

44  944. 
41  743. 
41  26O. 
41  2O9. 
4O  OOO. 
38752. 
36864. 
36  1OO. 
35713. 
35  156. 

35299. 
32  784. 
32  4O5. 
32365. 
31416. 

5.385 
5.189 
5.159 
5.156 
5.080 
5:000 
4.877 
4.826 
4.800 
4.762 

212.OO 
204.31 
2O3.13 
2O3.OO 
2OO.OO 

4 

M 

6 

2OO 

40 

0 

6 

SO  435. 
28953. 
28  350. 
28055. 
2761O. 

19.63 
18.68 
18.32 
18.10 
17.81 

196.85 
192.OO 
19O.OO 
188.98 
187.50 

i 

4.8 

19O 

35 

5 

35OO2. 
33  1O2. 
32  799. 
32  400. 
31389. 

27491. 
25999. 
2576O. 
25447. 
24647. 
24328. 
23569. 
23563. 
232O3. 
22698. 

17.44 
16.77 
16.62 
16.42 
15.90 

4.752 
4.621 
4.600 
4.572 
4.500 

187.O9 
181.94 
181.11 
180.00 
177.17 

4.6 

18O 



7 

4.5 

J4  4- 

7 

SO  976. 
3OOO9. 
30002. 
29541. 
289OO. 

15.69 
15.21 
15.20 
14.97 
14.64 
~13^5" 
13.79 
13.30 
12.97 
12.67 
"12.57 
12.37 
11.40 
11.34 
11.10 

4.470 
4.400 
4.400 
4.366 
4.318 

176.  OO 
173.23 
173.21 
171.88 
17O.OO 
165.36 
165.OO 
162.  02 
16O.OO 
158.12 
157.48 
156.25 
15O.OO 
149.61 
148.00 

3O 

ff 

17O 

4tt 

8 

27343. 
27225. 
2625O. 
256OO. 
25OO2. 

21  475. 
21  382. 
2O618. 
20106. 
19636. 

4.200 
4.191 
4.115 
4.064 
4.016 

6 

16O 

8 

25 

* 

4 

248O1. 
24414. 
22  5OO. 
22383. 
21  9O4. 

19479. 
19170. 
17671. 
17579. 
172O3. 

4.000 
3.969 
3.810 
3.800 
3.759 

38 

150 

x  9 

9 

7 

2O82O. 
2O  736. 
2OO89. 
2OOO2. 
19776. 

16351. 
16286. 
15778. 
15710. 
15532. 

10.55 
10.51 
10.18 
10.14 
10.02 
"9.931" 
9.621 
9.098 
9.079 
8.563 
8.365 
8.302 
8.042 
7.917 
7.601 

3.665 
3.658 
3.600 
3.592 
3.572 

144.29 
'1  44.OO 
141.74 
141.43 
140.63 

3  6 

A 

3  5 

14O 

196OO. 
18988. 
17956. 
17919. 
169OO. 

15394. 
14913. 
141O3. 
14073. 
13273. 

3.556 
3.500 
3.403 
3.400 
3.302 

14O.OO 
137.8O 
134.OO 
133.86 
130.00 

10 

3  4 

130 

1O 

8 

1651O. 
16384. 
15873. 
15625. 
15OO1. 

12967. 
12868. 
12466. 
1227O. 
11782. 

3.264 
3.251 
3.200 
3.175 
3.111 

128.49 
128.  OO 
125.99 
125.00 
122.48 

3  2 

K 

15 

3. 

12O 

11 

144OO. 
13951. 
13456. 
13092. 
12  152. 

11  31O. 
10954. 
10568. 
10283. 
9545. 

7.296 
7.069 
6.818 
6.634 
6.158 
"6.131 
6.081 
6.061 
6.020 
5.480 

3.048 
3.000 
2.946 
2.906 
2.800 

12O.OO 
118.11 
116.OO 
114.42 
11O.24 

9 

.  .  . 

a  a 

no 

12 

12  1OO. 
12OO1. 
11  963. 
11  881. 
1O816. 

9503. 
9426. 
9395. 
9331. 
8495. 

2.794 
2.783 
2.778 
2.769 
2.642 

11O.OO 
1O9.55 
1O9.38 
1O9.OO 
1O4.OO 

A 

12 

12      

Copyright,  1891,  by  CARL  HERING. 


26 


WIRING   COMPUTER. 


GAUGES  AND  SCALES. 

CROSS-SECTION. 

DIAMETER. 

j 

1 

Decimal. 

! 

6 
t 

M 

British. 

OJ 

3 
M 

ii 

js 

& 

Square 
Millimeters. 

Millimeters. 

1 

I. 

ii. 

in. 

IV. 

V.           VI. 

VII. 

VIII. 

IX. 

X. 

XI. 

XII. 

2.6 

10 

1O478. 
1O384. 
1OOOO. 
9688. 
9025. 

8  23O. 
8  155. 
7854. 
7609. 
7088. 

5.309 
5.261 
5.067 
4.909 
4.573 

2.600 
2.588 
2.540 
2.500 
2.413 

1O2.36 
1O1.9O 
1OO.OO 
98.43 
95.OO 

100 

2  5 

95 

13 

A 

!  4 

8928. 
8789. 
8464. 
8234. 
8100. 

7O12. 
6903. 
6648. 
6467. 
6362. 

4.524 
4.453 
4.289 
4.172 
4.104 

2.400 
2.381 
2.337 
2.305 
2.286 

94.49 
93.75 
92.OO 
9O.74 
9O.OO 
"89.45" 
86.62 
85.  OO 
83.  OO 
8O.81 
8O.OO 
78.74 
78.13 
75.OO 
74.81 

13 

.  .^.  . 

9O 

2  2 

8 

8OO1. 
7502. 
7226. 
6889. 
6530. 

6284. 
5892. 
5675. 
5411. 
5129. 

4.054 
3.801 
3.664 
3.491 
3.309 

2.272 
2.200 
2.160 
2.108 
2.053 

85 

14 

12 

2  O 

8O 

14 

64OO. 
6200. 
6104. 
5625. 
5596. 

5027. 
4870. 
4793. 
4418. 
4395. 
4072. 
4067. 
3944. 
3928. 
3848. 

3.243 
3.142 
3.093 
2.850 
2.835 

2.032 
2.000 
1.985 
1.905 
1.900 

* 

1.9* 

75 

15 

15 

13 

5184. 
6179. 
6022. 
6001. 
49OO. 

2.627 
2.624 
2.545 
2.534 
2.483 

1.82? 
1.828 
1.800 
1.796 
1.778 
"LTOr 
1.651 
1.628 
1.626 
1.600 

72.  OO 
71.96 
7O.87 
7O.72 
7O.OO 

1  8 

5 

7O 

.... 

7 

65 

16 

4480. 
4225. 
4107. 
4096. 
3968. 

3518. 
3318. 
3225. 
3217. 
3  116. 

2.271 
2.141 
2.081 
2.078 
2.011 

66.93 
65.  OO 
64.O8 
64.OO 
62.99 

14 

16 

1.6 

Me 

6O 

39O6. 
3600. 
3488. 
3364. 
3257. 
~~3T36T~ 
3O38. 
3O25. 
3OO1. 
262O. 
2583. 
25OO. 
24O1. 
23O4. 
2232. 
2  197. 
2O48. 
2O25. 
1875. 
1  764. 
1  624. 
1  6OO. 
1  55O. 
1296. 
1288. 

3O68. 
2827. 
2739. 
2642. 
2  558. 

1.979 
1.824 
1.767 
1.705 
1.650 
1.589 
1.539 
1.533 
1.521 
1.327 

1.588 
1.524 
1.500 
1.473 
1.450 
1.422 
1.400 
1.397 
1.391 
1.300 

62.  5O 
6O.OO 
59.  06 
58.OO 
57.07 

1  5 

17 

15 



17 

2463. 
2384. 
2376. 
2357. 
2O57. 

56.  OO 
55.12 
55.OO 
54.78 
51.18 

1  4 

55 

3 

1,3 

5O 

16 

2O29. 
1  964. 
1  886. 
181O. 
1  753. 

1.309 
1.267 
1.217 
1.167 
1.131 

1.291 
1.270 
1.245 
1.219 
1.200 

5O.82 
5O.OO 
49.OO 
48.  OO 
47.25 

18 

18 

1  2 

i 

17 

1  726. 
1  6O9. 
1  69O. 
1  473. 
1  385. 

1.113 
1.038 
1.026 
.9509 
.8938 
^8230- 
.8107 
.7854 
.6567 
.6527 

1.191 
1.150 
1.143 
1.100 
1.067 

46.88 
45.26 
45.OO 
43.31 
42.  OO 

45 

1  1 

19 

4O 

19 

18 

1276. 
1257. 
1217. 
1  O18. 
1  O12. 

1.024 
1.016 
1.000 
.9144 
.9116 

4O.3O 
4O.OO 
39.37 
36.OO 
35.89 
35.43 
35.OO 
32.  OO 
31.96 
31.  5O 

19 

.9 

85 



20 

21 

1  256. 
1225. 
1  O2  4. 
1O22. 
992.0 

985.9 
962.1 
8O4.2 
802.3 
779.3 
767.O 
7O6.9 
636.3 
615.8 
696.5 

.6362 
.6207 
.5188 
.5176 
.5027 

.9000 
.8890 
.8128 
.8118 
.8000 

21 

20 

,8 

* 

976.6 
9OO.O 
81O.1 
784.O 
759.5 

.4948 
.4560 
.4105 
.3972 
.3848 
-^425~ 
.3255 
.3167 
.2919 
.2827 

.7937 
.7620 
.7229 
.7112 
.7000 

31.25 
3O.OO 
28.46 
28.  OO 
27.56 
26.OO 
25.35 
25.  OO 
24.OO 
23.62 

... 

SO 

21 

28 



22 

22 

7 

26 

22 

676.O 
642.5 
625.O 
576.O 
658.  0 

63O.9 
6O4.6 
49O.9 
452.4 
438.3 

.6604 
.6438 
.6350 
.6096 
.6000 

25 
24 



23 

23 

fl 

22 

.  .  .  . 

24 

24 

23 

5O9.5 
48  4.  0 
4O4.1 
4OO.O 
387.5 

4OO.2 
380.1 
317.3 
314.2 
3O4.4 

.2581 
.245? 
.2047 
.2027 
.1963 

.5733 
.5588 
1    .5106 
.5080 
i    .5000 

22.57 
22.00 
20.1O 
2O.OO 
19.69 

24 

20 



25 

25 

5 

Copyright,  1891,  by  CARL  HEBING. 


TABLES   OF   WIRE   GAUGES. 


27 


GAUGES  AND  SCALES. 

CROSS-SECTION. 

DIAMETER. 

a 

~TT~ 

Millimeters. 

1 

Edison. 

e 
£ 

« 

British. 

|| 
•9 
M 

|j 

\i 

F 

§1 
u 

§ 

X. 

J 

i 

n. 

III. 

IV. 

v. 

VI. 

VII. 

VIII. 
361  .0 
324.O 
32O.4 
313.9 
289.  0 

IX. 
283.5 
254.5 
251.7 
246.5 
227.  0 
211.2 
2O1.1 
199.6 
194.8 
191.8 

XI. 

7482T 
.4572 
.4547 
.4500 
.4318 

XII. 
19.  OO 
18.  OO 
17.  9O 
17.72 
17.  OO 

18 



26 

26 

.1832 
.1642 
.1624 
.1590 
.1464 
7i363~ 
.1297 
.1288 
.1257 
.1237 

25 

45 

17 

16 



27 

27 

269.O 
256.O 
254.1 
248.O 
244.1 

.4166 
.4064 
.4049 
.4000 
.3969 

16.  4O 
16.OO 
15.94 
15.75 
15.63 

26 

£ 

15 

28 

225.  0 
219.0 
201.5 
196.0 
189.9 

176.7 
172.  0 
158.3 
153.9 
149.1 

.1140 
.1110 
.1021 
.09931 
.09621 

.3810 
.3759 
.3606 
.3556 
.3500 
T345T 
.3302 
.3211 
.3150 
.3048 

15.OO 
14.80 
14.20 
14.00 
13.78 

27 

35 

14 

28 

13 

29 

29 

185.0 
169.0 
159.8 
153.8 
144.O 

145.3 
132.7 
125.5 
120.8 
113.1 

.09372 
.08563 
.08097 
.07792 
.07296 
.07069 
.06818 
.06421 
.061  58 
.06087 

13.60 
13.  OO 
12.64 
12.4O 
12.OO 

28 

SO 

12 

30 

a 

31 

139.5 
134.6 
126.7 
121.5 
121.O 

109.5 
105.7 
99.53 
95.45 
95.  03 
91.61 
82.  3O 
78.94 
78.54 
7O.12 

.3000 
.2946 
.2859 
.2800 
.2794 

11.81 
11.  6O 
11.26 
11.O2 
11.  OO 

28 

29 

11        .... 

.26 

32 

116.6 
1O4.8 
1OO.5 
1OO.O 
89.28 

.05910 
.053  09 
.05092 
.05067 
.04524 

.2743 
.2600 
.2546 
.2540 
.2400 

1O.8O 
1O.24 
1O.O3 
10.00 
9.449 

30 

10 

31 

33 

914 

9 

.  .  .  . 

32 

34 

84.64 
81.  OO 
79.  7O 
75.02 
70.56 

66.48 
63.62 
62.  6O 
58.  9O 
55.42 

.04289 
.04104 
.04039 
.03801 
.03575 

.2337 
.2286 
.2268 
.2200 
.2134 
-^032" 
.2019 
.2000 
.1930 
.1800 
-J798" 
.1778 
.1727 
.1601 
.1600 
TI524 
.1426 
.1400 
.1321 
.1270 

9.2OO 
9.000 
8.928 
8.662 
8.4OO 

7i950 
7.874 
7.6OO 
7.O87 

31 

9,  9. 

35 

8 

33 

32 

64.OO 
63.  2O 
62.00 
57.76 
50.22 

5O.27 
49.64 
48.70 
45.36 
39.44 

.03243 
.03203 
.03142 
.02926 
.02545 
^02539" 
.02483 
.02343 
.02014 
.02011 

no 

36 

IB 

7 

.  .  .  . 

34 

33 

50.13 
49.00   . 
46.24 
39.75 
39.68 

39.37 
38.48 
36.32 
31.22 
31.15 

7.O8O 
7.OOO 
6.8OO 
6.  305 
6.299 

37 

34 

16 

6 

38 

36 

36.00 
31.53 
3O.38 
27.O4 
25.OO 
23.04" 
22.32 
19.83 
19.36 
18.75 

28.27 
24.76 
23.84 
21.24 
19.64 

.01824 
.01597 
.01539 
.013  70 
.01267 

Toner 

.01131 
.01005 
.0098  09 
.0095  03 
T008107 
.007967 
.007854 
.006561 
.006362 

6.OOO 
5.615 
5.512 
5.2OO 
5.OOO 

14 

39 

5 

35 

36 

.18 

37 

17.53 
15.57 
15.21 
14.73 

.1200 
.1131 
.1117 
.1100 

4.725 
4.453 
4.4OO 
4.331 

41 

1  1 

4 



36 

42 

38 

16.00 
15.72 
15.  5O 
12.96 
12.56 

12.57 
12.35 
12.17 
10.18 
9.859 

.1016 
.1007 
.1000 
.0914 
.0900 
T689T 
.0813 
.0800 
.0799 
.0762 

4.OOO 
3.965 
3.937 
3.6OO 
3.543 

.10 

43 

OP 

44 

39 

12.47 
lp.24 
9*920 
9.888 
9.OOO 

9.793 
8.042 
7.793 
7.766 
7.O69 

.006318 
.005191 
.0050  27 
.005010 
.004560 
.003972 
.003848 
.002918 
.0028  27 
.0020  27 
"^01963 
.0012  97 
.000730 
.0005.07 

3.531 
3.2OO 
3.15O 
3.145 
3.OOO 

2i756 
2.400 
2.362 
2.000 

OR 

40 

3 

07 

45 

7.84O 
7.595 
5.760 
5.580 
4.000 

6.158 
5.965 
4.524 
4.383 
3.142 

.0711 
.0700 
.0610 
.0600 
.0508 

To5oor 

.0406 
.0305 
.0254 

46 

00 

2 

47 

Oft 

48 
49 
5O 



3.875 
2.56O 
1.44O 
l.OOO 

3.044 
2.  Oil 
1.131 
.7854 

1.969 
1.6OO 
1.2OO 
l.OOO 

1 

Copyright,  1891,  by  CARL  HERING. 


28  WIRING   COMPUTER. 

COMPOUNDED  WIRES  OF  LARGE  CROSS-SECTION. 

In  wiring,  it  is  sometimes  necessary  to  use  wires  larger  than 
No.  00,  B.  &  S.  -  gauge.  It  then  becomes  necessary  to  compound 
the  wire,  not  only  because  No.  00  is  the  largest  size  which  it  is  prac- 
ticable to  lay  (unless  the  wire  is  stranded),  but  chiefly  because  the 
size  wanted  does  not  generally  happen  to  correspond  with  those  of 
the  gauge  numbers ;  and  as  the  length  of  the  wires  is  often  great, 
a  small  excess  over  the  required  cross-section  may  signify  a  con- 
siderable increase  in  the  cost.  In  such  cases  it  is,  therefore,  often 
desirable  to  obtain  the  closest  possible  approximation  to  the  re- 
quired cross-section  by  the  best  combination  of  the  sizes  in  the 
market. 

The  table  gives  every  possible  combination  of  the  four  largest 
wires  which  it  is  practicable  to  use,  namely,  Nos.  2,  1,  0  and  00  B. 
&  S.  gauge.  The  combinations  are  classified  in  the  order  of  their 
combined  sections.  Having  given  the  desired  cross-section  of  a 
compounded  wire,  for  instance,  400,000  circular  mils,  look  for  this 
size  in  the  second  column,  then  all  the  possible  combinations  which 
approximate  this  most  closely  will  be  found  near  to  it  in  the  adjoin- 
ing first  column.  In  this  case  it  will  be  seen  from  the 'table  that 
three  No.  0  wires  and  one  No.  1  will  give  it  very  closely ;  and 
there  is  no  other  combination  which  will  give  it  more  closely. 
Furthermore,  the  values  often  do  not  differ  very  much  from  each 
other,  thus  allowing  some  choice,  which  is  often  desirable.  For 
instance,  in  this  case  it  will  be  seen  that  three  No.  00  wires  will 
give  practically  the  same  close  approximation,  and  this  would  re- 
quire the  handling  of  only  one  size  of  wire,  which  is  sometimes 
greatly  to  be  preferred.  Again,  the  combination  just  above  this 
one,  namely,  four  No.  1  wires  and  one  No.  2,  is  also  quite  close  to 
the  desired  value ;  this  combination  would  be  preferable  if  there 
are  many  corners  and  bends,  as  the  wires  are  smaller. 

The  largest  limit  of  the  cross-sections  in  this  table  was  taken 
as  500,000  circular  mils,  or  a  little  less  than  four  00  wires.  For 
larger  sections,  as,  for  instance,  600,000,  select  from  the  table  any 
convenient  combination,  regardless  of  cross-section,  as,  for  instance, 
that  of  three  00  wires,  and  subtract  its  combined  section,  namely 
about  400,000,  from  the  600,000,  and  then  find  from  the  table  the 
best  combination  to  make  up  this  balance  of  200,000,  as,  for 
instance,  one  No.  00  and  one  No.  2  wire. 


COMPOUNDED   WIRES. 


29 


TABtE  OF 

COMPOUNDED  WIRES  OF  LARGE  SECTION. 

A  table  of  all  the  possible  combinations  of  numbers  00^  0,  1  and 
2,  B.  &  S.  wires  having  a  combined  cross-section  of  less  than 
500,000  circular  mils. 


It 

if 

Il 

•  I 

|| 

il 

B.  &  S.  (Ameri 
Gauge  Numb* 

1 

si 

S  0  « 

if 

11 

02    |> 

M 

jji 

oo-oo-oo-oo 
o-o-o-o-o 

532316. 
527  67O. 

OO-O-2-2-2 
0-2-2-2-2-2 

437  732. 
437399. 

O-O-2-2 
O-1-1-2 

343814. 
339295. 

OO-OO-1-1-2 

499919! 

OO-OO-l-l 
OO-  1-1-2-2 

433  540. 
433213. 

1-1-1-1 

00-00-2 

332  53  1! 

OO-1-1-2-2-2 
1-1-2-2-2-2-2 
OO-O-O-1-2 
O-O-1-2-2-2 

499  586. 
499  253. 
494214. 
493881. 

1-1-2-2-2-2 
OO-O-O-l 
O-O-1-2-2 
0-1-1-1-2 

432  88O. 
427841. 
427508. 
422  989. 

00-2-2-2 
2-2-2-2-2 
OO-O-l 
O-  1-2-2 

332  198. 
331  865. 
322  3O7, 
321974. 

00-0-1-1-1 
0-1-1-1-2-2 
0-0-0-0-2 
1-1-1-1-1-2 

489  695. 
489362. 
488  509. 
484843. 

0-0-0-0 
1-1-1-1-1 
OO-OO-1-2 
OO-1-2-2-2 

422  136. 
418  47O. 
416225. 
415892. 

1-1-1-2 
O-O-O 
OO-O-2 
O-2-2-2 

317455. 
316602. 
3O4986. 
3O4  653. 

O-O-O-l-l 
OO-OO-OO-l 
OO-OO-1-2-2 
OO-  1-2  -2  -2  -2 

483  99O. 
482931. 
482  598. 
482265. 

1-2-2-2-2-2 
OO-O-O-2 
O-O-2-2-2 
00-0-1-1 

415559. 
41O52O. 
410187. 
406001. 

00-1-1 
1-1-2-2 
O-O-l 
OO-1-2 

3OO  467. 
3OO  134. 
294762. 
283  146. 

1-2-2-2-2-2-2 
00-00-0-0 
00-0-0-2-2 
0-0-2-2-2-2 

481  932. 
477226. 
476893. 
476  560. 

0-1-1-2-2 
1-1-1-1-2 
O-O-O-l 
OO-OO-OO 

405  668. 
4O1  149. 
4OO296. 
399237. 

1-2-2-2 
O-O-2 
O-l-l 
OO-OO 

282813. 
277441. 
272922. 
266  158. 

00-0-1-1-2 
0-1-1-2-2-2 
OO-1-l-l-l 
1-1-1-1-2-2 

472  374. 
472  O41. 
467855. 
467  522. 

OO-OO-2-2 
OO-2-2-2-2 
2-2-2-2-2-2 
OO-O-1-2 

398  9O4. 
398571. 
398238. 
388  68O. 

OO-2-2 
2-2-2-2 
O-1-2 
1-1-1 

265825. 
265492. 
255  6O1, 
251  O82. 

O-O-O-1-2 
OO-OO-OO-2 
OO-OO-2-2-2 
OO-2-2-2-2-2 

466  669. 
465  6  1O. 
465277. 
464  944. 

O-  1-2  -2  -2 
OO-l-l-l 
1-1-1-2-2 
0-0-0-2 

388347. 
384  161. 
383828. 
382975. 

00-0 
0-2-2 
1-1-2 
OO-l 

238613. 
238280. 
233761. 
216773. 

2-2-2-2-2-2-2 
O-O-l-l-l 
00-00-0-1 
00-0-1-2-2 

464611. 
462  15O. 
455386. 
455053. 

0-0-1-1 
00-00-0 
00-0-2-2 
O-2-2-2-2 

378  456. 
371692. 
371  359' 
371  O26. 

1-2-2 
OOOO 
O-O 
OO-2 

21644O. 
211  6OO. 
211  O68. 
199452. 

O-  1-2  -2  -2  -2 
00-1-1-1-2 
1-1-1-2-2-2 
OO-O-O-O 

454720. 
450  534. 
45O2O1. 
449681. 

00-1-1-2 
1-1-2-2-2 
O-O-1-2 
O-l-l-l 

366  84O. 
366  5O7. 
361  135. 
356616. 

2-2-2 
O-l 
O-2 
000 

199  119, 
189228. 
171907. 
167805. 

O-O-O-2-2 
O-O-1-1-2 
O-1-l-l-l 
OO-OO-O-2 

449348. 
444829. 
44O31O. 
438  O65. 

OO-OO-l 
OO-1-2-2 
1-2-2-2-2 
OO-O-O 

349852. 
349519. 
349  186. 
344  147. 

1-1 
1-2 
00 
2-2 

167388. 
15O067. 
133  O79. 
132  746. 

30 


WIRING   COMPUTER. 


TABLE  OF 

WEIGHT  AOT>  RESISTANCE  OF  COPPER  WIRE. 


American  or  B.  &  S.  Wire 
Gauge. 

Decimal  Gauge  in  Mils. 

0  -»  1  New  British  Gauge,  or  Stand- 
00  I  ard  Wire  Gauge,  March,  1884. 

Diameter  in  Mils. 
(1  mil  =  .001  inch.) 

Cross-section  in 
Circular  Mils. 
(Circ.  mil  =  .7854  sq.  mil.) 

Cross-section  in  Square  Mils. 
(1  sq.  in.  =  1,000,000  sq.  mils.) 

Pounds  per  1000  Feet. 
tSp.gr.  8.889.) 

Feet  per  Pound. 

Ohms  per  1000  Feet. 
(1  mil-foot  10.605  legal  ohms.) 

Ohms  per  Pound. 

Feet  per  Ohm. 

K 

1 

500. 

5OO.OO 
!  464.OO 
460.00 
450.  OO 
432.  OO 
425.OO 
409.64 
4OO.OO 
375.OO 
372.00 

25OOOO. 
215296. 
211  6OO. 
2O2  5OO. 
186624. 
18O626- 
1678O5- 
16OOOO- 
14O625. 
138  384. 

196350. 
169093. 
166190. 
159043. 
146  574. 
141  8637 
131  790. 
125664. 
110  450. 
108687. 
104518. 
96211. 
95115. 
82958. 
82887. 
"824487 
70686. 
65732. 
59828. 
59390. 
121287 
49876. 
49087. 
42273. 
41339. 

756.6 
651.6 
64O.4 
612.9 
564.8 
534.2 
507.9 
484.2 
425.6 
418.8 
4O2.8 
37O.8 
366.5 
319.7 
319.4 

1.322 
1.535 
1.562 
1.632 
1.770 
1.829 
1.969 
2.065 
2.350 
2.388 
2.483 
2.697 
3.728 
3.128 
3.131 

.O4242 
.O4926 
.O5O12 
.O5237 
.O5683 
.O5871 
.O632O 
.O6628 
.07542 
.O7664 

.0000561 
.0000756 
.0000783 
.0000855 
.0001006 
.0001074" 
.0001244 
.0001369 
.0001772 
.0001830 
.0001979 
.0002335 
.0002389 
.0003141 
.0003146 
.0003180 
.0004326 
.0005003 
.0006039 
.0006127 
.0007955 
.0008689 
.0008971 
.001210 
.001265 

23573. 
2O3O1. 
19953. 
19O94. 
17598. 
17032. 
15823. 
15O87. 
1326O. 
13O49. 

17836. 
13228. 
12778. 
11702. 
9939. 
9310. 
8036. 
7306. 
5643. 
5465. 

4/0 

45O. 

5/6 

666 

425. 

4OO. 
375. 

4/0 

666 

oo 

350. 

00 

364.80 
35O.OO 
348.OO 
325.OO 
324.86 

133  O79. 
122  5OO. 
121  1O4. 
105625. 
1O5534. 
1O4976. 
90  000. 
83  694. 
76  176. 
75625. 
66373. 
63  504. 
62  500. 
53824. 
52  634. 
506257 
44  944. 
41  743. 
4O  OOO. 
86864. 
83  1O27 
32  4OO. 
SO  976. 
2625O. 
256OO. 
2O82O. 
2O  736. 
196OO. 
16900. 
16510. 

.07969 
.O8657 
.O8757 
.1O04 
.1OO5 

12548. 
11551. 
11419. 
996O. 
9951. 

5054. 
4282. 
4185. 
3184. 
3178. 
"11457" 
2312. 
1999. 
1656. 
1632. 
^2577" 
1151. 
1115. 
826.8 
790.6 
731.4 
576.4 
497.2 
456.6 
387.8 
~S12JT 
299.6 
273.8 
196.7 
187.0 

'6' 

325 

*i' 

300. 

0 

i 

324.OO 
3OO.OO 
289.  3O 
276.  OO 
275.00 
257.63 
252.  OO 
25O.OO 
232.00 
229.42 
225.OO 
212.00 
204.31 
2OO.OO 
192.  OO 
181794 
18O.OO 
176.  OO 
162.  02 
16O.OO 

317.7 
272.4 
253.3 
230.5 
228.9 
20079" 
192.2 
189.2 
162.9 
159.3 

3.148 
3.671 
3.948 
4.338 
4.369 
4.978 
5.203 
5.287 
6.139 
6.278 

.1O1O 
.1178 
.1267 
.1392 
.14O2 
.1598" 
.167O 
.1697 
.1970 
.2015 

9899. 
8486. 
7892. 
7183. 
7131. 
6258. 
5988. 
5893. 
5075. 
4963. 

2 

~sT 

275. 

3 

4 

25O. 

3 

225. 

'5' 

39  761. 
35  299. 
32784. 
31416. 
28953. 
25999. 
25447. 
24328. 
20618. 
20106. 

153.2 
136.0 
126.3 
121.1 
111.6 
100.2 
98.O6 
93.75 
79.45 
77.48 

6.527 
7.352 
7.916 
8.260 
8.963 
-9.982" 
10.20 
10.67 
12.59 
12.91 

.2O95 
.236O 
.2541 
.2651 
.2877 
.32  O4 
.3273 
.3424 
.4O4O 
.4143 
75094" 
.5114 
.5411 
.6275 
.6424 
76-473" 
.7365 
.7881 
.81OO 
.8765 

.001367 
.001735 
.002011 
.002190 
.002579 
.003198 
.003338 
.003652 
.005085 
.005347 

4774. 
4238. 
3936. 
3772. 
3476. 
3121. 
3055. 
2921. 
2475. 
2414. 
~T963. 
1955. 
1848. 
1594. 
1557. 

4 

2OO. 

'&' 

*7' 

~5~ 

iso. 

6 

^T 

160. 

8 

144.29 
144.OO 
14O.OO, 
13O.OO 
128.49 

16351. 
16286. 
15394. 
13273. 
12967. 

63.01 
62.76 
59.32 
51.15 
49.97 

15.87 
15.93 
16.86 
19.55 
20.01 

.008085 
.008150 
.009121 
.01227 
.01286. 

123.7 
122.7 
109.6 
81.51 
77.79 

9 

'  a' 

140. 
130. 

120. 

1O 
"lY 

128.OO 
12O.OO 
116.00 
114.42 
11O.OO 

16384. 
14400. 
13456. 
13092. 
12  1OO. 

12868. 
11  310. 
10568. 
10283. 
9503. 
8495. 
8155. 
7854. 
6648. 
6467. 
-63627 
5129. 
5027. 
4072. 
4067. 
^8487 
3225. 
3217. 
2827. 
2558. 
2463. 
2029. 
1964. 
1810. 
1609. 

49.59 
43.58 
4O.73 
39.63 
36.62 
32.73 
31.42 
8O.27 
25.62 
24.92 

20.17 
22.95 
24.67 
25.24 
27.31 

.01305 
.01690 
.01935 
.02044 
.02393 

1545. 
1358. 
1269. 
1236. 
1141. 

76.60 
59.18 
51.67 
48.92 
41.78 

& 

no. 

T2^ 

1O4.OO 
1O1.9O 
100.00 
92.OOO 
9O.742 

10816. 
10384. 
1OOOO. 
8464. 
8234. 
8  1OO. 
653O. 
6400. 
5184. 
5  179. 

30.55 
31.82 
33.04 
39.04 
40.13 

.98O5 
.021 
.061 
.253 
.288 

.02995 
.03250 
.03504 
.04891 
.05168 
76535T- 

.08218 
.08555 
.1304 
.1307 

1O2O. 
979.1 
942.9 
798.1 
776.4 
763.8 
615.7 
6O3.5 
488.8 
488.3 
462.  0 
387.2 
386.2 
339.5 
3O7.1 
295.7 
243.5 
235.7 
217.3 
193.1 

33.39 
20.77 
28.54 
20.44 
19.35 

10 

100. 

13 

11 

'12 

90. 

9O.OOO 
80.808 
80.000 
72.000 
71.962 

24.51 
19.76 
19.37 
15.69 
15.67 

40.79 
50.60 
51.63 
63.74 
63.81 

.309 
.624 
.657 
2.O46 
2.O48 

18.72 
12.17 
11.69 
7.669 
7.653 

80. 

14 
16 

13 

'l4 
*15 

7O. 

7O.OOO 
64.O84 
64.OOO 
60.000 
57.068 

4900. 
4107. 
4096. 
36OO. 
3257. 

14.88 
12.43 
12.40 
10.90 
9.857 
9.491 
7.817 
7.566 
6.973 
6.199 

67.43 
80.46 
80.67 
91.78 
101.5 

2.164 
2.582 
2.589 
2.946 
3.256 

.1459 

.2078 
.2084 
.2704 
.3304 

6.852 
4.813 
4.788 
3.698 
3.027 
~2780T 
1.904 
1.784 
1.515 
1.197 

'eo. 

16 

16 

17 

56.OOO 
50.821 
50.000 
48.000 
45.257 

3136. 
2583. 
25OO. 
23O4. 
2O48. 

105.4 
127.9 
132.2 
143.4 
161.3 

3.382 
4.1O6 
4.242 
4.6O3 
5.178 

.3646 
.5253 
.5607 
.6601 
.8353 

50. 

"l*8 

17 

According  to  the  Matthiessen  Standard  suggested  by  the  Committee  of  the 
Eng.,  these  resistances  are  for  pure  copper  wire  at  78)4  °  F. 


Amer.  Inst.  of  Elect. 


WEIGHT    AND    EESISTANCE. 


31 


i 

o 

02 

Decimal 
Gauge. 

New  British 
Gauge. 

Diam.  in  Mils. 

Cross-section 
in 
Circular  Mils. 

Cross-section 
in 
Square  Mils. 

If 
I 

i 
i 

Ohms 
per  1000  Feet. 

Ohms 
per  Pound. 

Feet 
per  Ohm. 

Pounds 
per  Ohm. 

"is" 

45. 

... 

45.OOO 
40.303 
40.000 
36.000 
35.891 

2025. 
1624. 
1600. 
1296. 
1288. 

1590. 
1276. 
1257. 
1018. 
1012. 
~9627l 
804.2 
802.3 
706.9 
636.3 

6.129 
4.916 
4.842 
3.922 
S.899 

163.2 
203.4 
206.5 
255.0 
256.5 

5.237 
6.529 
6.628 
8.183 
8.233 

.8545 
1.325 
1.369 
2.086 
2.112 

190.9 
153.2 
150.9 
122.2 
121.5 

1.170 
.7529 
.7306 
.4793 
.4735 
T4282— 
.2992 
.2978 
.2312 
.1873 

!l304 
.1178 
.09468 
.07408 

40. 

19 
2O 

26 

21 

357 

2*1 

35.OOO 
32.OOO 
31.961 
30.000 
28.462 

1  225. 
1024. 
1  O22. 
9OO.O 
81O.1 

3.708 
3.099 
3.O92 
2.724 
2.452 
2.373 
2.O46 
.944 
.743 
.542 

269.7 
322.7 
323.5 
367.1 
407.9 

8.657 
1O.36 
10.38 
11.78 
13.O9' 

2.335 
3.342 
3.358 
4.326 
5.339 

115.5 
96.56 
96.33 
84.86 
76.39 

SO. 

22 
'23 

28. 
26. 

22 

28.000 
26.000 
25.347 
24.OOO 
22.572 
22.OOO 
2O.1O1 
2O.OOO 
18.OOO 
17.900 

784.0 
676.  0 
642.5 
576.O 
5O9.5 

615.8 
530.9 
504.6 
452.4 
400.2 

42174 
488.8 
514.3 
573.6 
648.5 

13.53 
15.69 
16.51 
18.41 
2O.82 
21.91 
26.25 
26.51 
32.73 
33.1O 

5.701 
7.668 
8.490 
10.56 
13.50 

73.93 
63.74 
6O.68 
54.31 
48.  04 
45.64 
38.  1O 
37.72 
SO.55 
3O.21 

24. 

23 

24 
25 

22. 

24 

484.O 
404.1 
4OO.O 
324.O 
32O.4 

380.1 
317.3 
314.2 
254.5 
251.7 
211.2 
201.1 
199.6 
176.7 
172.0 
158.3 
153.9 
145.3 
132.7 
125.5 
120.8 
113.1 
105.7 
99.54 
95.03 

.465 
.223 
.211 
.98O6 
.9697 

682.7 
817.8 
826.0 
1020. 
1031. 

14.96 
21.47 
21.90 
33.38 
34.13 

.06685 
.04659 
.04566 
.02996 
.02930 

20. 
18. 

25 
26 

16.4OO 
16.OOO 
15.941 
15.OOO 
14.80O 

269.0 
256.O 
254.1 
225.0 
219.O 

.814O 
.7748 
.7690 
.6810 
.6629 

1229. 
1291. 
1300. 
1468. 
1508. 

39.43 
41.43 
41.74 
47.13 
48.42 

48.44 
53.47 
54.27 
69.22 
73.04 

25.36 

24.14 
23.96 
21.22 
20.65 

.02064 
.01870 
.01843 
.01445 
.01369 

26 

16. 

15. 

28* 

27 

14. 

2*9 

14.196 
14.OOO 
13.6OO 
13.OOO 
12.641 
12.4OO 
12.OOO 
11.6OO 
11.258 
1  l.OOO 

2O1.5 
196.0 
185.0 
169.  0 
159.8 

144.O 
134.6 
126.7 
121.  0 

.6099 
.5932 
.5598 
.5115 
.4836 
.4654 
.4358 
.4O73 
.3836 
.3662 

1640. 
1686. 
1786. 
1955. 
2068. 
2149. 
2295. 
2456. 
2607. 
2731. 

52.63 
54.11 
57.34 
62.75 
66.36 
68797" 
73.65 
78.81 
83.68 
87.65 

86.29 
91.21 
102.4 
122.7 
137.2 
.148.2 
169.0 
193.5 
218.2 
239.3 

19.00 
18.48 
17.44 
15.94 
15.O7 
14.5O 
13.58 
12.69 
11.95 
11.41 

.01159 
.01096 
.009763 
.008151 
.007288 
7006747" 
.005918 
.005167 
.004584 
.004178 

28 

13. 

12. 

-36" 
sY 

.2{* 

11. 

1O.8OO 
1O.O25 
1O.OOO 
9.2OOO 
9.OOOO 

116.6 
1OO.5 
1OO.O 
84.64 
81.OO 

91.61 
78.94 
78.54 
66.48 
63.62 

.353O 
.3O42 
.3O27 
.2562 
.2451 

2833. 
3288. 
3304. 
3904. 
4079. 

9O.92 
1O5.5 
1O6.1 
125.3 
130.9 

257.6 
346.9 
350.4 
489.1 
534.1 

11.  OO 
9.477 
9.429 
7.981 
7.638 

.003883 
.002883 
.002854 
.002044 
.001872 

SO 

1O. 

33 
34 

9. 

31 

8.9277 
8.4OOO 
8.OOOO 
7.9503 
7.6000 
7.0800 
7.0000 
6.8000 
6.3049 
6.OOOO 

79.7O 
7O.56 
64.OO 
63.2O 
57.76 

62.60 
55.42 
50.27 
49.64 
45.36 
—39.37 
38.48 
36.32 
31.22 
28.27 

.2412 
.2136 
.1937 
.1913 
.1748 

4146. 
4683. 
5163. 
5228. 
5720. 

133.1 
150.3 
165.7 
167.8 
183.6 

551.6 
703.8 
855.5 
877.1 
1050. 

7.515 
6.653 
6.O35 
5.96O 
5.446 

.001813 
.001421 
.001169 
.001140 
.0009521 

35 

*;*32' 

8. 

36 

33 

7. 

37* 

5O.13 
49.OO 
46.24 
39.75 
36.00 

.1517 
.1483 
.1399 
.12O3 
.1O9O 

6592." 
6743. 
7146. 
8312. 
9178. 

211.6 
216.4 
224.1 
266.8 
294.6 

1395. 
1459. 
1639. 
2218. 
2704. 

4.727 
4.62O 
4.36O 
3.748 
3.395 

.0007170 
.0006852 
.0006102 
.0004510 
.0003698 
.0002836 
.0002087 
.0001784 
.0001515 
.0001122 

34 
*36 

6. 

38 

5.6147 
5.2OOO 
5.OOOO 
4.8OOO 
4.4526 

31.53 
27.  04 
25.00 
23.04 
19.83 

24.76 
21.24 
19.64 
18.10 
15.57 

.O9541 
.08  184 
.O7566 
.06973 
.O6OOO 

10482. 
12220. 
13217. 
14341. 
16666. 

336.4 
392.2 
424.2 
46O.3 
534.9 
547.8 
662.8 
674.5 
818.3 
85O.6 

3526. 
4792. 
5607. 
6601. 
8915. 

2.973 
2.55O 
2.357 
2.173 
1.869 

'  6*. 

39 
40 

37 

38 

4. 

41 
42 

4.4OOO 
4.OOOO 
3.9652 
3.6OOO 
3.5311 

19.36 
16.00 
15.72 
12.96 
12.47 
1O.24 
9.888 
9.000 
7.840 
6.76O 

2.'560 
1.44O 
l.OOO 
1273. 

15.21 
12.57 
12.35 
10.18 
9.793 

•  O5859 
•O4842 
.O4758 
.O3922 
.O3774 

17067. 
20651. 
21015. 
25495. 
26500. 

9349. 
13688. 
14175. 
20863. 
22540. 

1.826 
1.5O9 
1.483 
1.222 
1.176 

.0001070 
.0000731 
.0000706 
.0000479 
.0000444 

43 

39 

.  .  . 

*4O 

44 

3.2OOO 
3.1445 
3.0000 
2.8000 
2.4OOO 
2.OOOO 
1.6OOO 
1.2OOO 
l.OOOO 
35.682 

8.042 
7.766 
7.069 
6.158 
4.524 
—37142 
2.011 
1.131 
.7854 
1000. 

259510. 
8329. 
1470. 
8.329 
1470. 

.O3O99!  32267. 
.02993!  33416. 
.02724    36713. 
.02373!  42146. 
.01743)  57364. 

1O36. 
1O73. 
1178. 
1353. 
1841. 

33418. 
35841. 
43260. 
57009. 
105620. 
1T90107 
534690. 
1689900. 
3504100. 
2.162 

.9656 
.9324 
.8486 
.7393 
.5431 

.0000299 
.0000279 
.0000231 
.0000175 
.0000095 

3. 

45 
46 

48 
49 
6O 

"a. 

.O1211 
.00775 
.OO436 
.OO3O3 
3.853 
l.OOO 
1OOO. 
32.10 
5.665 
.O321O 
5.665 

82604. 
129068. 
229456. 
330416. 
259.5 
~1660T 
1.000 
31.16 
176.5 
31156. 
176.5 

2651. 
4143. 
7366. 
1O6O5. 
8.329 

.3772 
.2414 
.1358 
.0943 
12O.1 

.0000046 
.0000019 
.0000006 
.0000003 
.4626 
.03116 
31156. 
32.10 
1.000 
.0000321 
1.000 

1. 

18.177 
574.82 
1O2.98 
43.266 
3.2566 
43.266 

33O.4 
33O418. 
1O6O5. 
1872. 
1O.61 
1872. 

32.10 
.O321O 
l.OOO 
5.665 
1OOO. 
5.665 

32.10 
.0000321 
.03116 
1.000 
31156. 
1.000 

31.16 
31166. 
1OOO. 
176.5 
l.OOO 
176.5 

32 


WIRING   COMPUTER. 


TABLE  OF 
TEMPERATURE  CORRECTIONS  FOR  COPPER  WIRE. 

Instead  of  using  the  usual  formula  for  correcting  the  resistance 
of  copper  wire  for  temperature,  the  calculation  may  be  very  much 
simplified  by  finding  the  mil-foot  resistance  K  in  the  first  column 
of  the  accompanying  table,  corresponding  to  the  given  tempera- 
ture, and  using  the  simple  formula  R  =  -~  K,  in  which  R  is  the 
required  resistance  in  legal  ohms  at  the  given  temperature ;  L  is 
the  length  in  feet;  d  is  the  diameter  of  the  wire  in  mils,  or  d2  the 
cross-section  in  circular  mils;  and  K  is  the  mil-foot  resistance 
taken  from  the  table.  As  this  constant  contains  only  two  digits, 
one  of  which  is  unity,  the  calculation  is  a  very  simple  one. 

This  table  is  based  on  the  Matthiessen  standard  suggested  by 
the  Committee  of  the  American  Institute  of  Electrical  Engineers, 
namely  9.612  legal  ohms  for  a  mil-foot  at  0°  C. 


10.00 


10.10 


10.20 


10.30 


50.47 


55.15 


59.79  15.44 


64.40  18.00 


10.26 


12.86 


10.40  ;68.97  20.54 
.50  173.51  23.O6 


10.50 


1O.6O  78.O1 


25.56 


10.70  82.47  28.04 


stance  per 
1-foot  in 
al  Ohms. 
K. 

£ 

y,  *j 

III 
ii« 

A 

II 

lfl 

&c3Q 

10.80 
10.00 

86.90 
91.31 

30.50 
32.95 

11.00 

95.69 

35.38 

11.10 

100.04 

37.80 

11.20 

104.36 

40.20 

11.3O 

108.64 

42.58 

11.  4O 

112.9O 

44.95 

11.50 

117.14 

47.3O 

WEIGHT   OF   INSULATED   WIRE. 


33 


WEIGHT  OF  INSULATED  WIRE  FOR  WIRING. 

FOB  COMPUTING  THE  COST  WHEN  MAKERS  GITE  THE  PRICES  PER 
POUND  INSTEAD  OF  PER  100.  FEET. 


B.  &  S.  Wire  Gauge  Numbers. 

WEIGHTS  IN  POUNDS  PER  100.  FEET. 

B.  &  S.  Wire  Gauge  Numbers. 

American  Electrical  Works. 
Underwriters  Braided  Electric  Light 
Line  Wire. 

American  Electrical  Works. 
Weather-proof  Braided  Electric  Light 
Line  Wire. 

Holmes,  Booth  and  Haydens. 
K.  K.  Triple-braided. 

{§ 

1 

ri 

<j 

A.  F.  Moore.  Weather-proof. 

A.  F.  Moore.  Fire  and  Weather-proof. 

N.  Y.  Insulated  Wire  Co. 
Competition  Line  Wire. 

N.  Y.  Insulated  Wire  Co. 
Other  Wires. 

Okonite  Electric  Light  Line  Wires. 
Plain  Insulation. 

Okonite  Electric  Light  Line  Wires. 
Braided  Insulation. 

Simplex. 
T  Z  R  Weather-proof. 

Simplex. 
Caoutchouc,  Plain  Rubber. 

Simplex. 
Caoutchouc  with  Protective  Braids. 

OOOO 

ooo 

00 
0 

1 

Solid 
Solid 
Solid 
Solid 

7O.6 
6O.O 
5O.O 
4O.O 

75.  0 
65.O 
44.0 
35.0 

73.  0 
53.7 
42.3 
33.2 

88.7 
65.5 
51.6 
41.7 

40.6 

... 

93.8 
69.2 
56.4 
43.7 

99.0 
71.4 
60.0 
47.3 

74.6 
60.6 
47.7 
38.2 

78.1 
63.3 
50.1 
41.8 

92.6 
8O.9 
67.2 
57.0 

OOOO 
OOO 
00 

o 

1 
1 
2 
2 

3 
3 

4 
4 

45.0 
35.0 

42.5 
33.  0 

1 
1 

2 
2 

3 
3 
4 
4 

Solid 
Stranded 
Solid 
Stranded 

29.0 

27.O 

31.6 

28.4 

27.  0 

33.4 

33.3 

•tj 

34.5 
36.2 
28.2 
3O.O 

36.7 
38.7 
29.7 
32.5 

31.1 
2.38 

31.4 
33.  0 
25.5 
26.5 

37.2 
41.2 
29.  0 
31.9 

24.0 

20.  4 

27.9 

23.5 

22.4 

27.7 

28.6 

Solid 
Stranded 
Solid 
Stranded 

19.5 

17.7 

24.O 

19.0 

18.0 

22.3 

21.1 

I 

£ 

*» 

20.6 
24.O 
17.O 
2O.1 

22.  0 
25.7 
18.4 
21.4 

19.2 
16.8 

20.  3 
22.1 
16.7 
17.1 

24.O 
25.8 
18.8 
19.1 

15.5 

14.0 

15.8 

15.5 

14.7 

18.2 

18.2 

5 
5 
6 
6 

7 
7 
8 
8 

9 
1O 
11 
12 

13 
14 
15 
16 

Solid 
Stranded 
Solid 
Stranded 

12.5 

11.0 

12.9 

12.5 

11.9 

17.4 

14.3 

)  feet  and  nc 

12.6 
10*.  4 

13.6 
13.8 
1O.7 
11.7 

16.3 

12*.  7 
13.5 

5 
5 
6 
6 

7 
7 
8 
8 

9 
10 
11 
12 

13 
14 
15 
16 

17 
18 
19 
20 

16.3 
11.6 
13.6 

17.7 
12.5 
15.0 

1O.5 

9.5 

1O.9 

1O.2 

9.7 

12.  0 

11.1 

8.1 

Solid 
Stranded 
Solid 
Stranded 

7.3 

8.3 

8.1 

7.7 

10.3 

and  sold  by  the  1<X 

lo'.e 

7.O 
8.8 

5.6 
5.2 

l'l'.5 
7.6 
9.6 

8.9 

8.5 

1O.2 

8.2 
8.7 

7.0 

5.7 

7.3 

6.5 

7.1 

6.9 

6.6 

8.9 

7.2 

7.6 

7.0 
7.4 

5.5 
5.0 
4.O 
2.9 

2.4 
2.1 
1.7 
1.3 

1.2 
1.0 
.90 
.85 

4.9 
4.5 
3.5 
2.5 

2.1 
1.8 
1.5 
1.3 

1.2 
1.0 
.90 
.85 

5.5 
5.2 
3.95 
3.4O 

5.4 
4.7 

5.1 
4.5 

6.8 
6.0 

•  

Solid 
Solid 
Solid 
Solid 

6.1 
5.6 

6.4 
5.3 

5.9 
4.6 

2.85 

2.6 

3.5 



1 

3.3 

3.8 

3.7 

3.1 

4.2 

Solid 
Solid 
Solid 
Solid 

2.27 

2.00 

1.9 

2.7 

2.4 

2.7 

2.4 

2.1 

2.9 

1.89 

1.3O 

1.25 

1.8 



1.55 

1.86 

1.8 

1.4 

1.9 

17 
18 
19 
2O 

Solid 
Solid 
Solid 
Solid 

1.5O 

1.O5 
.90 
.85 

l.OO 
.85 
.80 

1.4 
1.24 
1.17 

1.10 

1.38 

1.5 

1.0 

1.4 

.95 

1.21 

34 


WIRING   COMPUTER. 


TABIuE  OF  HEATING  LIMITS 

OB 

MAXIMUM  SAFE  CARRYING  CAPACITY 

OF  INSULATED  WIRES. 

These  numbers  were  calculated  from  the  formula  given  by  the 
Edison  Company  on  their  standard  tables,  namely :  max.  amp.  = 

CITC'™/1    I   which  reduces  to  the  more  convenient  form : 
104.    J 


.031  J2  diam* 


The  numbers  are  only  approximate,  as  they  depend  on  the 
nature  of  the  surroundings  of  the  wire,  thickness  of  insulation, 
etc.  The  temperature  given  with  the  formula  is  50°  C.  or  122°  F. 


& 

II 

I 

Greatest  number  of  LAMPS  of  the  following  different 
currents  per  lamp  : 

lORSE- 

on  a 

Ircuit.* 

tl 

*2 

I 

(For  the  THSKB-WIRI  system  use  double  the  number  of  lamps.) 

iP 

21 

« 

.45 

.50 

.55 

.60 

.65 

.70 

.75 

.80 

.90 

1.00 

1.10 

JPl 

« 

0000 

303. 

673 

6O6 

651 

505 

466 

433 

404 

379 

336 

303 

275 

89.3 

oooo 

ooo 

254. 

566 

509 

463 

424 

392 

364 

339 

318 

283 

254 

231 

75.0 

ooo 

oo 

214. 

476 

428 

389 

357 

329 

3O6 

285 

267 

238 

214 

195 

63.1 

oo 

o 

180. 

400 

360 

327 

3OO 

277 

257 

24O 

225 

2OO 

18O 

163 

53.  0 

o 

1 

151. 

336 

302 

275 

252 

232 

216 

2O1 

189 

168 

151 

137 

44.5 

1 

2 

127. 

282 

254 

231 

212 

195 

181 

169 

159 

141 

127 

115 

37.5 

2 

3 

107. 

237 

213 

194 

178 

164 

152 

142 

133 

119 

1O7 

97 

31.4 

3 

4 

9O. 

2OO 

18O 

163 

15O 

138 

128 

12O 

112 

1OO 

9O 

82 

26.5 

4 

6 

75. 

167 

151 

137 

125 

116 

1O7 

1OO 

94 

84 

75 

68 

22.2 

5 

6 

63. 

14O 

127 

115 

105 

97 

9O 

84 

79 

70 

63 

67 

18.6 

6 

7 

63. 

118 

1O6 

97 

89 

82 

76 

71 

66 

69 

63 

48 

15.7 

7 

8 

45. 

89 

81 

74 

69 

64 

59 

66 

49 

45 

40 

13.2 

8 

9 

37. 

83 

75 

68 

62 

57 

63 

6O 

47 

41 

37 

34 

11.0 

9 

10 

31. 

70 

63 

57 

62 

48 

45 

42 

39 

35 

31 

29 

9.32 

10 

11 

26. 

59 

53 

48 

44 

41 

38 

35 

33 

29 

26 

24 

7.81 

11 

12 

22. 

49 

45 

40 

37 

34 

32 

3O 

28 

25 

22 

20 

6.58 

12 

13 

19. 

42 

38 

34 

31 

29 

27 

25 

23 

21 

19 

17 

5.54 

13 

1/4 

16. 

35 

32 

29 

26 

24 

22 

21 

20 

17 

16 

14 

4.66 

14 

15 

13. 

29 

26 

24 

22 

20 

19 

17 

16 

14 

13 

12 

3.89 

15 

16 

11. 

24 

22 

20 

18 

17 

16 

15 

14 

12 

11 

10 

3.27 

16 

17 

9.4 

21 

19 

17 

16 

14 

13 

12 

11 

10 

9 

8 

2.75 

17 

18 

7.9 

17 

16 

14 

13 

12 

11 

1O 

10 

9 

8 

7 

2.32 

18 

19 

6.6 

14 

13 

12 

11 

10 

9 

8 

8 

7 

6 

6 

1.95 

19 

20 

5.6 

12 

11 

10 

9 

8 

8 

7 

7 

6 

6 

5 

1.63 

2O 

21 

4.7 

10 

9 

8 

8 

7 

6 

6 

6 

6 

4 

4 

1.37 

21 

22 

3.9 

8 

7 

7 

6 

6 

5 

5 

5 

4 

4 

3 

1.15 

22 

*  These  numbers  represent  ELECTRICAL  HORSE-POWER  ;  for  MECHANICAL  HORSE-POWER  mul- 
tiply these  numbers  by  the  efficiency  of  the  motor. 

Copyright,  1891,  by  CARL  HERINO. 


HORSE-POWER   TABLE.  35 


TABLE  OF  HOKSE-POWER  EQUIVALENTS. 

In  wiring  for  motors,  the  wireman  desires  to  know  what  cur- 
rent he  must  wire  for,  when  the  horse-power  is  given.  To  do  this 
he  must  find  the  current  corresponding  to  this  horse-power.  The 
horse-power  tables  as  usually  published  are  not  well  suited  for 
this,  as  they  are  arranged  for  the  reverse  of  this  calculation. 
Furthermore,  their  ranges  and  the  large  number  of  decimals  are 
far  beyond  the  limits  used  by  wiremen,  and  the  tables  are,  there-' 
fore,  unnecessarily  large  and  cumbersome.  The  following  table 
has  therefore  been  prepared  especially  for  wiremen,  the  ranges 
being  chosen  to  cover  those  with  which  he  has  to  deal,  namely, 
from  .1  to  30  H.P.  and  from  45  to  250  volts.  It  gives  the  currents 
in  amperes  required  for  different  horse-powers  at  different  voltages. 

For  horse-powers  greater  than  the  limit  of  the  table,  find  the 
current  for  J,  £,  or  J  of  this  horse-power,  and  then  multiply  the 
current  obtained  by  2,  3,  or  4,  respectively.  For  an  odd  number 
of  horse-powers,  as  21.5,  for  instance,  add  the  current  for  1.5  to 
that  for  20  H.P. 

For  two,  three,  or  four  times  the  voltage  given  in  the  table, 
divide  the  current  obtained  from  the  table  by  two,  three,  or  four, 
respectively. 

The  figures  at  the  top  may  be  read  as  amperes  if  those  in  the 
body  of  the  table  are  read  as  volts.  If  many  determinations  are 
to  be  made  for  one  particular  voltage  it  is  recommended  to  draw 
a  red  line  on  each  side  of  that  particular  column. 

For  very  large  horse-powers,  or  when  greater  accuracy  is  re- 
quired than  is  given  in  the  table,  the  calculation  should  be  per- 
formed. The  current  in  amperes  is  equal  to  the  horse-power  mul- 
tiplied by  746  and  divided  by  the  voltage. 

These  figures  are  for  electrical  horse-powers  supplied 
to  the  motor.  If  the  column  of  horse-powers  is  to  rep- 
resent mechanical  horse-powers  delivered  by  the  motor, 
then  divide  the  current  obtained  from  the  table  by  the 
efficiency  of  the  motor  (in  units,  thus,  70),  and  multiply 
by  100,  which  will  give  a  proportionately  greater  current. 


36 


WIRING   COMPUTER. 


HORSE-POWER  EQUIVALENTS  IN  VOLTS  AND  AMPERES. 


Horse 
Power 


.1 
.15 
.2 
.25 


.35 

.4 

.45 

.5 

.55 

.6 

.65 

.7 

.75 


.85 

.9 

.95 

'.I 

.2 
.3 
.4 
.5 
.6 

1.7 
1.8 
1.9 


2.4 
2.6 
2.8 


3.4 

3.6 

3.8 

4. 

4.2 

4.4 

4.6 

4.8 

5. 

6.5 


6.5 

7. 

7.5 


8.5 

9. 

9.5 
1O. 
10.5 

11. 

11.5 

12. 

12.5 

13. 

14. 
15. 
16. 
17. 
18. 

19. 
2O. 
22. 
25. 
SO. 


VOLTS. 


50        55 


65       70    I    75 


100 


105     110      115 


4.15  3.73 
4.97 


1.66  1.49  1.36  1.24X15  1.O7|.995  .932  .878  .829  .785  .746  .71OI.678  .649 
2.49  2.24  2. 04  1.87, 17.211. 6O|1. 49  1. 4o|l.32!  1.24'1. 18  1.12  1.O7  1.O2  973 
3.32  2.99  2.71!2.492.3O2.13il.99  1.8711. 76'l.65  1.57  1.49  1.42  1  36  1.3O 
3.39  3.11  2.87:2. 67J2. 49  2.33  2.2O  2. 07;  1.96  1.87  1.78  1.7O1  1  62 
4.O7  3.73  3.44  3.2O  2.99  2.8OJ2.63  2.49  2.36|2.24  2.13  2.O4  1.95 

4.75  4.354.O2  3.73  3.48  3.263.O7  2.9O2.75!2.61  2.49  2  37  2  27 
5.434.97  4.59  4.263.98  3.73  3.51  3.32  3. 14  2.98  2.84  2°71  2^60 
6.10:5.59  5. 16  4.8O  4.48  4.2O  3.95  3.73  3.53  3.36  3.2O  3.O5  2.92 
6.78|6.22i5.745.33  4.97  4.564.39  4.153.93  3.73  3.55  3.39  3.24 
7.46,6.8416.31:5.86,5.4715.1314.83,4.56,4.32  4.103.91,3.7313.57 

A     C*£*    A     *%•*(  . 


5.8O  5.22 
6.63  5.97 

6.71 

7.46 
9.12  8.21 

9.95  8.95  8.14!7.46!6.89'6.405.97i5.59'5.27|4.97l4.71  4.48'4.26'4  O7!3  89 
1O.8;9.7O  8.82  8.O8  7.46  6.93  6.46  6.O6  5.71  5.39  5. 1O  4.85  4.62  4  41  4  22 
1 1.6  !  1O.5  9.49  8.7O  8.O3  7.46  6.96  6.53  6. 14  5.8O  5.5O  5.22  4.97  4  75!  4  54 
1 1.2  1O.2  9.32  8.6l!7.99  7.46  6.99  6.58  6.22  5.89  5.59  5.33  5*09  4  86 
10.9,9.95,9.18  8.52  7.96,7.46  7.O2  6.63  6.28  5.97  5.68  5. 42  5^9 


14.9 
15.8 


18.2 


24.9 
26.5 


i  :  i 


11.9 

12.7  11.5il0.69.769.06;8.45l7.937.46!7.05'6.68!6.346.04'5.76!5.51 
13.4il2.2jl  1.2  1O.39. 59  8.958. 39(7.9O  7.46  7. 07  6.71  6.39  6.1O  5.84 
14.2-12.9  11.8  1O.91O.1  9.4518.868.34  7.87  7.46  7. 09  6.75  6  44  6.16 
1 4.9  •  13. 6, 12. 4  11.5  1O.7  9.95  9.32  8.78  8.29  7.85  7.46  7.1O6  78  6  49 
16.4  1 4.9,13.7:12. 6;il. 7110.9.10.3:9. 65  9. 12  8. 64,8.21  7.82  7.46:  7.13 


17.9 
19.4 


23.9 


28.2 '25.4 


21.7 
23.1 


14.9  13.8J12.8I11.9  11.21 


16.3 

16.2;14.9 
19.O  17.4  16.O 


20.4  18.7 


17.2 


19.9  18.4 


21.1  19.5  18.1 


1O.5  9.95  9.42  8.95  8.52!8.14'  7.78 
11.411O.8I1O.2  9. 7O  9. 24  8.82  8.43 
12.3!  11.6jll.O  1O.49.95  9. 49I9.O8 
16.O  14.9J14.O  13.2il2.4  11.8ill.2llO.7!lO  2  9.73 


13.9>12.9jl2.1 


14.9 


17.1 


13.9113.1 


15.9  14.9 


14.0  13.2 ,12.6:11.9' 11.4  10.9!  1O.4 
16.0!  1 5.8!  14.9!l4.l'l3.4'l2.7!  12.1111.6   11.0 


I  I 


29.9  26.9  24.422.420.7  19.2  17.9}  16.8'  15.8<14.9;i4.i;i3.4  12.8 '12.2   11.7 
31.5  28.4,25.723.621.8  2O.3  18.9117. 7jl6.7i15.8J14.9  14.2  13.5  12.91  12.3 
27.1 124.923. 02 1.3  19.9  18.7  17. 6J 16. 5i  15.7!  14.9  14.2  13.e'  13.O 
29.8  27.4  25.3,23.5,2 1.9,20.5  19.3  18.2J17.3l  16.4  15.6  14.9J  14.3 

32.629.8  27.6  25.e'23. 9  22. 421. 1'19.9'l8. 9  17.9'l7.1  16.3   15.6 


36.5  32.8 


39.8 

43.1 


49.7 
53.1 


35  8 

38. 8  135.3  32.3  29.9;27.7  25.9  24:322.8  21. 6  20. 4  19.418.5  17:e!  16.9 


46.4  41.8  '38. OI34.8  32.  li29. 9  27.9  26.1  24.6  23.2  22. 0  2O.9  19.9  19. 01  18.2 
44.8  |4O.7  37.3  34.4  32. 0  29.9  28. 0  26.3  24.9  23.6  22.4  21.3  2O.4  19.5 


47.8  43.439.8J36.7J34.2.31.8  29.9  28.1  26.5  25.1  23.9  22.7:21.7  2O.8 
5O.7  46.1  42.3  39. 0  36.2  33.8  31. 7J29.9  28.2'26.7  25.4  24.2  23.1  22.1 


597  |537  488  44s  4ls  384  35.8  33.6,3.e29.8  2a. 

63.O  56.7|51.5  47.2  43.6  40.  5  37.8  35.433.431.529.9  28.427.O25  8  24.7 

66.3!59.7!54.3  49.7  45.942.639.8  37.3  35.1  33.2  31.4  29.8  28.4  27  1  26.O 

69.6J62.7 

65.6 


79.6 
82.9 


91.2  82.1 
99.5  89.5 


1O8. 
116. 
124. 
133. 

141. 
149. 
158 
166. 
174. 


199. 
2O7. 
216. 


71.6 
74.6 


112. 
119. 

127. 
134. 
142. 


28.5 


57.0  52.2  48.2  44.8  41.8:39.2  36.9  34.8  33.O  31.3,29.8|28.5 

59.7  54.7  50.5  46.9'43.8  41. OS38.6'36. 5  34.6-32.S!31.3  29.8 
62.457.2|52.8  49.0  45.8  42.9  4O.4  38.  Ij36.1  ;34.3:32. 731.21  29.8 

65.1  59.7  55.1  51.2  47.7  44.8  42.1  39.8  37.7  35.8  34.1;32.6i  31. 1 
67.8|62.2  57.4  53.3  49.7  45.6  43.9i41.~  " 

74.668.463.1 


58.6  54.7  51.3  48.3,45.6,43 


.5  39.3  37.3  35.5  33. 9|  32.4 
.6J43.2  41.0,39.1  37.3  35.7 


81.4'74.6'68.9  64.O  59.7'55.9  52.7149.7  47. l!44.8'42.6;4O.7l  38.9 
97. 0  88.2  8O.8  74.6  69.3  64.6  6O.6  57. 1  53.9I51.O  48.5  46.2  44  1142.2 
1O5.  94.9  87.O  8O.3J74.6  69.6;65.3  61.4  58. 0  55. 0  52.2  49.7:47.5;  45.4 

1O2. |93.2  86.1179. 9J74.6  69.9  65.8  62.2  58.9  55.9  53.3  50. 9  48.6 


1O9.!99.5:91.8|85.2  79.6  74.6  7O.2, 66.3  62.8j59.7|56.8|54.2  51.9 

1 15.  lO6.i97.6  9O.6  84.5  79.3  74.6  7O.5'66.8  63.4  6O.4i57.6  55.1 
122. 1112. 11O3.  95.9  89.583.9  79. 0  74.6  7O.7  67.1  63.9  61. 0:  58.4 
129. !ll8.  1O9.J1O1.  94.5  88.6  83.4  78.7  74.6  7O.9  67.564.4  61.6 
136.:  124.' 1 15.I1O7.  99.5  93.2  87.8  82.9  78.5  74.6  71. 0  67.8!  64.9 
142.  131. J121. 1112.  1O4.  97.9,92.1,87.1i82  478.474.6,71.2,68.1 


.1126.  117.  1O9.! 


149.  137.1126. |117.|lO9.!lO3.  96. 591. 2|86. 482.1  78.2  74.6J  71.3 


1 56.|  143.  132. :  123.1 114.  1O7. 
163.1149.  138. !  128.  1 19.il  12. 


172. 
179 
187J170.  155.  144J130.  124.  117! 


194.  J176.  162.  149.! 


209. 


224. 
239. 


254. 


16O. 


19O.  174.! 
2O4.  187.  172. 
217.  199.1184. 
231.  211.;i95 
244.l224.i207. 


45     1    50 


139. ,129. ,121. 

149.  139J131 
16O.  149.J14O. 
171J159.J149. 
181.  169.  159. 
192. '179.  168. 


1O1.  95.3,90.3  85.8  81.7  78. 0  74.6 
1O5.  99.5  94.2  89.5  85.2  81.41  77.8 
11O..1O4.  98.2  93.388.884.8:81.1 
1 14.1 1O8.,  1 02.  97.0,92.4  88.2;  84.3 


140. 
149. 
158. 


116.I11O. 
124.1118. 
132.J126. 
141.  134. 
149.  141. 


257.;236.  218.  2O3.  189.  177.  167.  158. 
271.  249.  23O.  213.:  199.  187.  176.  165. 
298.  274.  253.  235.  219. 12O5.  193. '182. 
339.  311.|287.  267.  249.  233.  22O.I2O7. 
4O7.  373.  344.  32O.  299.  23O.  263.  249. 


55   I    60   I    65    |    70   I    75    I    80 


85 


90 


104.99.594.9190.8 


107. 


97.3 


149.  142.  135.  129.  123 
149.  142.H36.  13O. 
164.  156.S149.'  143. 

196.  187.1178.  17O.I  162. 

236.224.213.204.    195. 


100  I    105  I    110       115 


Copyright,  1891,  by  CARL  HERING. 


HORSE-POWER   TABLE. 


37 


HORSE-POWER  EQUIVALENTS  IN  VOLTS  AND  AMPERES. 


Horse 
Powe 

VOLTS. 

Horse 
Power 

120 

130 

140 

150 

160 

170 

180 

190      200 

210 

220 

230 

240 

250 

.1 

.622 

.574 

.533 

.497 

.466 

.439 

.414 

.393  .373 

.355 

.339 

.324 

.311 

.298 

.1 

.15 

.932 

.861 

.799 

.746 

.699 

.658 

.622 

.589  .560 

.533 

.509 

.487 

.466 

.448 

.15 

.2 

1.24 

1.15 

1.07 

.995 

.932 

.878 

.829 

.7851.746 

.711 

.678 

.649 

.622 

.597 

.2 

.25 

1.55 

1.44 

1.33 

1.24 

1.17 

1.1O 

1.O4 

.982 

.932 

.888 

.848 

.811 

.777 

.746 

.25 

.3 

1.87 

1.72 

1.6O 

1.49 

1.4O 

1.32 

1.24 

1.18 

1.12 

1.O7 

1.O2 

.973 

.932 

.895 

.3 

.35 

2.18 

2.O1 

1.87 

1.74 

1.63 

1.54 

1.45 

1.37 

1.30 

1.24 

1.19 

1.14 

1.09 

.04 

.35 

.4 

2.49 

2.3O 

2.13 

1.99 

1.87 

1.76 

1.66 

1.57 

1.49 

1.42 

1.36 

1.3O 

1.24 

.19 

.4 

.45 

2.80 

2.58 

2.4O 

2.24 

2.1O 

1.98 

1.87 

1.77 

1.68 

1.6O 

1.53 

1.46 

1.40 

.34 

.45 

.5 

3.11 

2.87 

2.66 

2.49 

2.33 

2.19 

2.07 

1.96 

1.87 

1.78 

1.7O 

1.62 

1.55 

.49 

.5 

.55 

3.42 

3.16 

2.93 

2.74 

2.56 

2.41 

2.28 

2.16 

2.O5 

1.95 

1.87 

1.78 

1.71 

.64 

.55 

.6 

3.73 

3.44 

3.20 

2.98 

2.80 

2.63 

2.49 

2.36 

2.24 

2.13 

2.03 

1.95 

1.87 

1.79 

.6 

.65 

4.O4 

3.73 

3.46 

3.23 

3.O3 

2.85 

2.69 

2.55 

2.43 

2.31 

2.2O 

2.11 

2.  02 

1.94 

.65 

.7 

4.35 

4.O4 

3.73 

3.48 

3.26 

3.O7 

2.9O 

2.75 

2.61 

2.49 

2.37 

2.27 

2.18 

2.O9 

.7 

.75 

4.66 

4.3O 

4.OO 

3.73 

3.5O 

3.29 

3.11 

2.94 

2.80 

2.66 

2.54 

2.43 

2.33 

2.24 

.75 

.8 

4.97 

4.59 

4.26 

3.98 

3.73 

3.51 

3.32 

3.14 

2.98 

2.84 

2.71 

2.6O 

2.49 

2.39 

.8 

.85 

5.29 

4.88 

4.53 

4.23 

3.96 

3.73 

3.52 

3.34 

3.17 

3.O2 

2.88 

2.76 

2.64 

2.54 

.85 

.9 

5.60 

5.16 

4.8O 

4.48 

4.2O 

3.95 

3.73 

3.53 

3.36 

3.  2O 

3.05 

2.92 

2.80 

2.69 

.9 

.05 

5.91 

5.45 

5.06 

4.72 

4.43 

4.17 

3.94 

3.73 

3.54 

3.38 

3.22 

3.08 

2.95 

2.83 

.95 

1. 

6.22 

5.74 

5.33 

4.97 

4.66 

4.39 

4.14 

3.93 

3.73 

3.55 

3.39 

3.24 

3.11 

2.98 

1. 

1.1 

6.84 

6.31 

5.86 

5.47 

5.13 

4.83 

4.56 

4.32 

4.1O 

3.91 

3.73 

3.57 

3.42 

3.28 

1.1 

1.2 

7.46 

6.89 

6.39 

5.97 

5.6O 

5.27 

4.97 

4.71 

4.48 

4.26 

4.O7 

3.89 

3.73 

3.58 

.2 

1.3 

8.  OS 

7.46 

6.93 

6.46 

6.O6 

5.71 

5.39 

5.1O 

4.85 

4.62 

4.41 

4.22 

4.O4 

3.88 

.3 

1.4 

8.70 

8.  OS 

7.46 

6.96 

6.53 

6.14 

5.80 

5.5O 

5.22 

4.97 

4.75 

4.54 

4.35 

4.18 

.4 

1.5 

9.32 

8.61 

7.99 

7.46 

6.99 

6.58 

6.22 

5-89 

5.6O 

5.33 

5.O9 

4.87 

4.66 

4.48 

.5 

1.6 

9.95 

9.18 

8.52 

7.96 

7.46 

7.  02 

6.63 

6.28 

5.97 

5.68 

5.43 

5.19 

4.97 

4.77 

.6 

1.7 

1O.6 

9.75 

9.O6 

8.45 

7.92 

7.46 

7.O5 

6.68 

6.34 

6.O4 

5.77 

5.51 

5.28 

5.O7 

.7 

1.8 

11.2 

1O.3 

9.59 

8.95 

8.39 

7.90 

7.46 

7.O7 

6.71 

6.4O 

6.11 

5.84 

5.19 

5.37 

.8 

1.9 

11.8 

1O.9 

1O.1 

9.45 

8.86 

8.34 

7.87 

7.46 

7.09 

6.75 

6.44 

6.16 

5.91 

5.67 

.9 

2. 

12.4 

11.5 

1O.7 

9.95 

9.32 

8.78 

8.29 

7.85 

7.46 

7.11 

6.78 

6.49 

6.22 

5.97 

2. 

2.2 

13.7 

12.6 

11.7 

1O.9 

10.3 

9.65 

9.12 

8.64 

8.  2O 

7.82 

7.46 

7.14 

6.84 

6.56 

2.2 

2.4 

14.9 

13.8 

12.8 

11.9 

11.2 

10.5 

9.95 

9.42 

8.95 

8.52 

8.14 

7.78 

7.46 

7.16 

2.4 

2.6 

16.2 

14.9 

13.9 

12.9 

12.1 

11.4 

1O.8 

1O.2 

9.7O 

9.24 

8.82 

8.43 

8.  OS 

7.76 

2.6 

2.8 

17.4 

16.1 

14.9 

13.9 

13.1 

12.3 

11.6 

11.0 

1O.4 

9.95 

9.49 

9.O8 

8.7O 

8.36 

2.8 

3. 

18.7 

17.2 

16.  0 

14.9 

14.0 

13.2 

12.4 

11.8 

11.2 

1O.7 

1O.2 

9.73 

9.32 

8.95 

3. 

3.2 

19.9 

18.4 

17.1 

15.9 

14.9 

14.0 

13.3 

12.6 

11.9 

11.4 

10.9 

1O.4 

9.95 

9.55 

3.2 

3.4 

21.1 

19.5 

18.1 

16.9 

15.9 

14.9 

14.1 

13.4 

12.7 

12.1 

11.5 

11.0 

10.6 

1O.1 

3.4 

3.6 

22.4 

20.7 

19.2 

17.9 

16.8 

15.8 

14.9 

14.1 

13.4 

12.8 

12.2 

11.7 

11.2 

1O.7 

3.6 

3.8 

23.6 

21.8 

20.2 

18.9 

17.7 

16.7 

15.8 

14.9 

14.2 

13.5 

12.9 

12.3 

11.8 

11.3 

3.8 

4. 

24.9 

23.  0 

21.3 

19.9 

18.7 

17.6 

16.6 

15.7 

14.9 

14.2 

13.6 

13.  0 

12.4 

11.9 

4. 

4.2 

25.1 

24.1 

22.4 

2O.9 

19.6 

18.4 

17.4 

16.5 

15.7 

14.9 

14.2 

13.6 

13.1 

12.5 

4.2 

4.4 

27.4 

25.2 

23.5 

21.9 

2O.5 

19.3 

18.2 

17.3 

16.4 

15.6 

14.9 

14.3 

13.7 

13.1 

4.4 

4.6 

28.6 

26.4 

24.5 

22.9 

21.5 

20.2 

19.1 

18.1 

17.2 

16.3 

15.6 

14.9 

14.3 

13.7 

4.6  • 

4.8 

29.9 

27.6 

25.6 

23.9 

22.4 

21.1 

19.9 

18.8 

17.9 

17.1 

16.3 

15.6 

14.9 

14.3 

4.8 

5. 

31.1 

28.7 

26.6 

24.9 

23.3 

21.9 

20.7 

19.6 

18.7 

17.8 

17.0 

16.2 

15.5 

14.9 

5. 

6.5 

34.2 

31.6 

29.3 

27.4 

25.6 

24.1 

22.8 

21.6 

2O.5 

19.5 

18.7 

17.8 

17.1 

16.4 

5.5 

e. 

37.3 

34.4 

32.  0 

29.8 

28.O 

26.3 

24.9 

23.6 

22.4 

21.3 

20.3 

19.5 

18.7 

17.9 

6. 

6.5 

4O.4 

37.3 

34.6 

32.3 

3O.3 

28.5 

26.9 

25.5 

24.3 

23.1 

22.  0 

21.1 

2O.2 

19.4 

6.5 

7. 

43.5 

4O.2 

37.3 

34.8 

32.6 

3O.7 

29.  0 

27.5 

26.1 

24.9 

23.7 

22.7 

21.8 

2O.9 

7. 

7.5 

46.6 

43.  0 

4O.O 

37.3 

35.O 

32.9 

31.1 

29.4 

28.  0 

26.6 

25.4 

24.3 

23.3 

22.4 

7.5 

8. 

49.7 

45.9 

42.6 

39.8 

37.3 

35.1 

33.2 

31.4 

29.8 

28.4 

27.1 

26.  0 

24.9 

23.9 

8. 

8.5 

52.9 

48.8 

45.3 

42.3 

39.6 

37.3 

35.2 

33.4 

31.7 

3O.2 

28.8 

27.6 

26.4 

25.4 

8.5 

9. 

56.  0 

51.6 

48.  0 

44.8 

42.  0 

39.5 

37.3 

35.3 

33.6 

32.  0 

SO.  5 

29.2 

28.0 

26.9 

0. 

9.5 

59.1 

54.5 

5O.6 

47.2 

44.3 

41.7 

39.4 

37.3 

35.4 

33.8 

32.2 

30.8 

29.5 

28.3 

9.5 

10. 

62.2 

57.4 

53.3 

49.7 

46.6 

43.9 

41.4 

39.3 

37.3 

35.5  33.9 

32.4 

31.1 

29.8 

10. 

10.5 

65.3 

60.3 

56.O 

52.2 

49.0 

46.1 

43.5 

41.2 

39.2 

37.3 

35.6 

34.1 

32.6 

31.3 

1O.5 

11. 

68.4 

63.1 

58.6 

54.7 

51.3 

48.3 

45.6 

43.2 

41.O 

39.1 

37.3 

35.7 

34.2 

32.8 

11. 

11.5 

71.5 

66.0 

61.3 

57.2 

53.6 

5O.5 

47.7 

45.2 

42.9 

4O.9 

39.O 

37.3 

35.7 

34.3 

11.5 

12. 

74.6 

68.9 

63.9 

59.7 

56.  0 

52.7 

49.7 

47.1 

44.8 

42.6 

4O.7 

38.9 

37.3 

35.8 

12. 

12.5 

77.7 

71.7 

65.6 

62'.  2 

58.3 

54.9 

51.8 

49.1 

46.6 

44.4 

42.4 

40.5 

38.9 

37.3 

12.5 

13. 

8O.8 

74.6 

69.3 

64.6 

6O.6 

57.1 

53.9 

51.0 

48.5 

46.2 

44.1 

42.2 

40.4 

38.8 

13. 

14. 
15. 

87.0 
93.2 

8O.3 
86.1 

74.6 
79.9 

69.6 
74.6 

65.3 
69.9 

61.4 
65.8 

58.O 
62.2 

55.0 
58.9 

52.2 
56.01 

5s!sl 

47.5 
5O.9 

45.4 
48.7 

43.5 
46.6 

41.8 
44.8 

14. 
15. 

16. 

99.5 

91.8 

85.2 

79.6 

74.6 

7O.2 

66.3 

62.8  59.7 

56.8154.3 

51.9 

49.7 

47.7 

16. 

17. 

1O6. 

97.5 

9O.6 

84.5 

79.2 

74.6 

70.5 

66.8  63.4 

6O.4  57.7 

55.1 

52.8 

50.7 

17. 

18. 

112. 

1O3. 

95.9 

89.5 

83.9 

79.0 

74.6 

7O.7 

67.1 

64.O 

61.1 

58.4 

51.9 

53.7 

18. 

19. 

118. 

1O9. 

1O1. 

94.5 

88.6 

83.4 

78.7 

74.6 

7O.9 

67.5 

64.4 

61.6 

59.1 

56.7 

19. 

2O. 

124. 

115. 

1O7. 

99.5 

93.2 

87.8 

82.9 

78.5 

74.6 

71.1 

67.8 

64.9 

62.2 

59.7 

2O. 

22. 

137. 

126. 

117. 

109. 

103. 

96.5 

91.2 

86.4 

82.  0 

78.2 

74.6 

71.4 

68.4 

65.6 

22. 

25. 

155. 

144. 

133. 

124. 

117. 

110. 

104. 

98.2 

93.2 

88.8 

84.8 

81.1 

77.7 

74.6 

25. 

SO. 

187. 

172. 

16O. 

149. 

14O. 

132. 

124. 

118. 

112. 

1O7. 

1O2. 

97.3 

93.2 

89.5 

SO. 

120 

~130 

140 

7so~ 

160 

170 

180 

190 

200 

210 

220 

230 

240 

"250 

Copyright,  1891,  by  CARI,  HERING. 


WIRING   COMPUTER. 


WIRING  TABLES. 

The  following  set  of  five  tables  will  be  found  very  convenient 
for  a  special  and  limited  class  of  work.  They  give  the  distances  in 
feet  up  to  1,000,  to  which  each  size  of  wire  of  the  B.  &  S.  gauge 
will  carry  any  given  number  of  lamps  at  stated  losses.  Usually 
such  tables  are  arranged  differently,  the  sizes  of  wire  being  given 
for  each  number  of  lamp  at  regularly  increasing  distances.  By 
the  present  arrangement,  however,  a  table  of  the  same  size  will 
cover  a  very  much  greater  range  of  values ;  and,  as  it  gives  actual 
values  instead  of  approximate  ones,  it  is  even  more  accurate,  not- 
withstanding its  increased  range.  It  is  also  more  convenient  to 
use,  because  instead  of  following  two  rows  of  figures  to  their  inter- 
section, one  lirie  of  figures  is  followed  around  a  corner,  which,  for 
rapid  work  and  a  condensed  table,  is  less  confusing. 

Such  tables  are  necessarily  limited  to  special  lamps  and  losses. 
The  values  assumed  in  the  following  set  have  been  chosen  so  as  to 
cover  as  wide  a  range  as  possible,  and  to  suit  the  usual  lamps, 
voltages  and  losses.  For  lamps  of  slightly  different  currents  than 
those  assumed,  it  need  be  remembered  merely,  that  if  the  current 
is  slightly  greater,  the  distances  must  be  taken  slightly  less  than 
those  given,  and  vice  versa.  For  half  the  losses  given,  take  half 
the  distances,  or  better,  take  the  distances  for  double  the  number 
<3f  lamps.  Although  calculated  for  five  special  cases,  these  tables 
may  be  used  also  for  quite  a  number  of  other  lamps,  voltages  and 
losses.  These  have  all  been  classified  in  the  index  on  the  opposite 
page  to  facilitate  finding  which  table  to  use. 

It  should  be  distinctly  understood  that  these  tables  are  not 
to  be  used  for  successive  parts  of  branched  circuits,  unless  the 
loss  is  understood  to  be  for  that  part  only.  For  instance,  suppose 
the  loss  in  a  building  is  2  per  cent,  and  a  certain  circuit  branches 
into  two,  say  at  one-fourth  of  the  distance  to  the  lamps,  it  is  not 
correct  to  find  the  size  of  the  first  part  for  a  two  per  cent,  loss,  and 
then  the  sizes  of  the  second  parts  for  a  2  per  cent,  loss,  as  this 
would  give  a  total  loss  of  4  per  cent.  But  if  the  loss  on  the  first 
part  be  taken  as,  say  \  per  cent.,  and  that  on  the  second  parts,  the 
remaining  \\  per  cent.,  then  the  tables  may  be  used  for  each  part 
separately.  This  error  has  been  made  frequently  by  presumably 
reliable  wiremen. 


WIRING  TABLES. 


39 


INDEX  TO  WIRING  TABLES. 


TWO  WIRE  SYSTEM. 


Fora  50  volt  lamp,  taking  1.1  amperes. 

50             "                 ill        « 
50             "                  1.           «« 
50             "                  1.          " 
50             "                  1.          " 

Loss  2.2 
"    4.4 
"    9.6 
"     2. 
"    4. 
"     8.8 

56  or  1.1  volts,  use  table  No.  1. 
2.2       "                            2. 
4.8                                      3. 
1.         "                              1. 
2.         "                "            2. 
4.4       "                "            3. 

For  a  55  volt  lamp,  taking  1.1  amperes. 

55             "                  l!l         " 
55             "                  1.           " 
55             "                  1.          " 
55             "                  1.          " 

Loss  2. 
**     4. 
"    8.8 
"    1.8 
"    3.6 
"    8. 

<fr  or  1.1  volts,  use  table  No.  1. 
2.2       "                "            2. 
4.84      «•                              3. 
1.         "                              1. 
2.         '                 "            2. 
4.4       '                 "            3. 

For  a  75  volt  lamp,  taking  .75  amperes. 
75             "                    .75       f' 
75             "                    .75       " 
75             "                    .75       " 

Loss  1. 
"    2. 
"    4.4 
"    8.8 

<f>  or   .75  volts,  use  table  No.  1. 
1.5       «                             2. 
3.3       «                 "            3. 
6.6       '                 "            4. 

For  a  75  volt  lamp,  taking  .6   amperes. 

75             "                    !6         " 
75             "                    .6         " 

Loss   .8 
"     1.6 
"    3.5 
"    7. 

%  or   .6  volts,  use  table  No.  1. 
1.2       '                               2. 
2.64      «                 "            3. 
5.3   (approx.)    "            4. 

For  a  100  volt  lamp,  taking  .5   amperes. 
100             "                    .5         "• 
100             "                    .5         " 
100              "                     .5         " 
100              "                     .5         " 

Loss   .5 

**         1* 

"    2.2 
"    4.4 

"    8.8 

%  or  .5  volts,  use  table  No.  1. 

£2       "              "           3! 
4.4        "                 "             4. 
8.8       "                "            5. 

For  a  110  volt  lamp,  taking   .5   amperes. 
110             •'                    .5        f' 
110             "                    .5         " 
110             "                    .5         " 
110             "                    .5         " 

Loss   .45 
"       .9 

"     2. 
"     4. 

'•     8. 

<fc  or   .5  volts,  use  table  No.  1. 

4.'4        "                 "             4.' 
8.8       "                "            5. 

For  a  110  volt  lamp,  taking   .45  amperes. 
110             "                    .45       f' 
110              "                     .45       " 
110              "                     .45       " 
110              "                     .45       " 

Loss   .41 
"      .8 
"    1.8 
"    3.6 
"     7.2 

%  or   .45  volts,  use  table  No.  1. 
(ap.)    .9       "                "            2. 
2.    (approx.)      "            3. 
4.    (approx.)      "            4. 
8.    (approx.)      "            5. 

THREE  WIRE  SYSTEM. 

For  a  100  volt  lamp,  taking  .5   amperes.    Loss   .55  <jo  or   .55  volts  per  lamp,  use  table  No.  3. 

100  .5         "'  "     1.1  1.1      «  4. 

100  "  _  .5  _  "     2.2  2.2  _  «  _  R 

For  a  110  volt  lamp,  taking  .5   amperes.    Loss   .5    $  or   .55  volts  per  lamp,  use  table  No.  3. 

'  '  2.2      "  "  5.' 


_  110             "  _  .5         "  "     2. 

For  a  110  volt  lamp,  taking  .45  amperes.  Loss   .4 

110                                 .45       fi  "       .9 

_  110              "                   .45       "  "     1.8 


or   .5   (approx. 

1.  (approx. 

2.  (approx. 


use  table  No.  3. 
"  5! 


MOTOR  CURRENTS. 


For  a   50  volt  circuit,  and  a  loss  of  2    $  or  1. 
50              "  "          4.  2. 

50               "  "  8.8  4.4 

50 « "         17.6  8.8 

For  a   55  volt  circuit,  and  a  loss  of  1.8  (ap.)  1. 

8  «     if¥ti 

65  " "        16.  8.8 

For  a  75  volt  circuit,  and  a  loss  of  1.3 


volt,  use  table  No.  1. 
2. 

"  3. 

"  4. 


volt,  use  table  No.  1. 

2. 

3. 

"  4. 


2.7 
5.9 
11.7 


ap.)  1. 
ap.;  2. 
ap.)  4.4 
ap.)  8.8 


volt,  use  table  No.  1. 

"  3! 

"  4. 


For  a  100  volt  circuit,  and  a  loss  of  1.    $  or  1. 
100  "  "          2.  2. 

100  "  "  4.4  4.4 

100  "  "  8.8  8.8 

100  "  "         17.6          17.6 


volt,  use  table  No.  1. 

3. 

4. 

"  5. 


For  a  110  volt  circuit,  and  a  loss  of    .9  (ap.)  1. 
110  "  "          1.8  (ap.)  2. 

110  "  "  4.  4.4 

110  "  "  8.  8.8 

110  "  "         16.  17.6 


volt,  use  table  No.  1. 
**  2. 

3. 

4. 
"  5. 


a  220  volt  circuit,  and  a  loss  of    .9  (ap.)  2. 
220  "2.  4.4 

220  "  "  4.  8.8 


volt,  use  table  Nc.  2. 

"  3. 

4. 

**  5. 


40 


WIRING   COMPUTER. 


0  I  f  ^^i  ^  iif 


WJ      £ 


2  2  2  2  2 


l 


WIRING    TABLES. 


41 


I  'o'o'p'o'3'p'o'o    5 

I 


42 


WIRING  COMPUTER. 


ooo     Q   a  a  a 

.  %     SS3  I  ***  o 

ft     §  c3«Srt     S 


fc!  HI S«  -§ 

srj     i 

M^  2 

ll^-4 


SI  i!!!f!lfl|- 


| 

1*1  SaaaaaaaS 

"S   >>c3Scs55S«3   es 


IPllflfJflfS 

S  &  ^13333333  w, 

I  i^^^^^^lll 

»d  b   ft  8 

^  H  ffaftaaacxo,  S 

glflllJtSIJ 

1  1  11111111  1 

_§     2§:3!3£SSS£ 

3         iH  .^^ 

eScjeeeaesaaca   « 


f 


i  CO  00  •*'  W  <N  i-i 


43 


p  e^.  e*. 

'£          H-i 


44 


WIRING  "COMPUTED, 


0 

! 
| 

« 
£» 


ifl 

•sa 
§3 
*£ 

I! 


I 


ThackaraMfg.Co 


and  1^26  Chestnut  Street, 


PHILADELPHIA,  PA. 


Mantafactuirer®  of 


Electroliers 

and 

Gas  Fixtures. 


SPECIAL  DESIGNS 
FOR 

Hotels, 

Theatres, 
Office  Buildings 

AND 

Marine  Work. 


ALFRED  F.  MOOSE,  Established  182O.  WBBTBRN  AGKKT, 

CHARLES    C.    KIXG,  G.    A.   HARMOTJNT, 

ANTOINK  BOURNOHVILLE.  149  Wabash  Ave.,  Chicago,  111 

ALFRED  F.  MOORE, 


MANUFACTURER   OF 


INSULATED 


ELECTRIC  WIRE, 

FLEXIBLE  CORDS  AND  CABLES, 

of  every  description. 


200  N.  Third  St.,  Philadelphia,  Pa. 


THE 


Runner  and  Gotta  Percty  Insulating  Co. 


MANUFACTURERS   OF 


RUBBER  COVERED  WIRE 

For  Concealed  Work,  For  Electric  Railways, 

For  Underground  Work,  For  Manufactories* 

For  Public  Buildings. 


Adopted  by  the  NAVY  DEPARTMENT,  and  in  use  on  all  the  vessels  of 
the  United  States  Navy. 

Our  insulation  fulfills  all  requirements  in  places  demanding  the  "  Beet,"  and 
in  that  field  finds  no  successful  competitors. 


Office  and  Works,  Branch  Office, 

Glenwood,  Yonkers,  N.  Y.  315  Madison  Ave.,  New  York. 

(Cot.  42d  St.) 
W.  M.   HABIRSHAW,  General  Manager. 


m»-fff^ym\ 


^B^^^» 


465768 


UNIVERSITY  OF  CAUFORNIA  LIBRARY 


I 
- 


